@contents
+
@ifnottex
@node Top, Overview, (dir), (dir)
@top @value{tramp} version @value{trampver} User Manual
For the developer:
-* Files directories and localnames:: How file names, directories and localnames are mangled and managed.
+* Files directories and localnames::
+ How file names, directories and localnames
+ are mangled and managed.
* Traces and Profiles:: How to Customize Traces.
* Issues:: Debatable Issues and What Was Decided.
Configuring @value{tramp} for use
-* Connection types:: Types of connections made to remote hosts.
+* Connection types:: Types of connections to remote hosts.
* Inline methods:: Inline methods.
* External methods:: External methods.
@ifset emacsgvfs
@chapter An overview of @value{tramp}
@cindex overview
-After the installation of @value{tramp} into your @value{emacsname}, you
-will be able to access files on remote hosts as though they were
-local. Access to the remote file system for editing files, version
-control, and @code{dired} are transparently enabled.
-
-Your access to the remote host can be with the @command{rsh},
-@command{rlogin}, @command{telnet} programs or with any similar
-connection method. This connection must pass @acronym{ASCII}
-successfully to be usable but need not be 8-bit clean.
-
-The package provides support for @command{ssh} connections out of the
-box, one of the more common uses of the package. This allows
-relatively secure access to hosts, especially if @command{ftp}
-access is disabled.
-
-Under Windows, @value{tramp} is integrated with the PuTTY package,
-using the @command{plink} program.
-
-The majority of activity carried out by @value{tramp} requires only that
-the remote login is possible and is carried out at the terminal. In
-order to access remote files @value{tramp} needs to transfer their content
-to the local host temporarily.
-
-@value{tramp} can transfer files between the hosts in a variety of ways.
-The details are easy to select, depending on your needs and the
-hosts in question.
-
-The fastest transfer methods for large files rely on a remote file
-transfer package such as @command{rcp}, @command{scp}, @command{rsync}
-or (under Windows) @command{pscp}.
-
-If the remote copy methods are not suitable for you, @value{tramp} also
-supports the use of encoded transfers directly through the shell.
-This requires that the @command{mimencode} or @command{uuencode} tools
-are available on the remote host. These methods are generally
-faster for small files.
-
-@value{tramp} is still under active development and any problems you encounter,
-trivial or major, should be reported to the @value{tramp} developers.
-@xref{Bug Reports}.
+@value{tramp} is for transparently accessing remote files from within
+@value{emacsname}. @value{tramp} enables an easy, convenient, and
+consistent interface to remote files as if they are local files.
+@value{tramp}'s transparency extends to editing, version control, and
+@code{dired}.
+
+@value{tramp} can access remote hosts using any number of access
+methods, such as @command{rsh}, @command{rlogin}, @command{telnet},
+and related programs. If these programs can successfully pass
+@acronym{ASCII]} characters, @value{tramp} can use them.
+@value{tramp} does not require or mandate 8-bit clean connections.
+
+@value{tramp}'s most common access method is through @command{ssh}, a
+more secure alternative to @command{ftp} and other older access
+methods.
+
+@value{tramp} on Windows operating systems is integrated with the
+PuTTY package, and uses the @command{plink} program.
+
+@value{tramp} mostly operates transparently in the background using
+the connection programs. As long as these programs enable remote login
+and can use the terminal, @value{tramp} can adapt them for seamless
+and transparent access.
+
+@value{tramp} temporarily transfers a remote file's contents to the
+local host editing and related operations. @value{tramp} can also
+transfer files between hosts using standard Emacs interfaces, a
+benefit of direct integration of @value{tramp} in @value{emacsname}.
+
+@value{tramp} can transfer files using any number of available host
+programs for remote files, such as @command{rcp}, @command{scp},
+@command{rsync} or (under Windows) @command{pscp}. @value{tramp}
+provides easy ways to specify these programs and customize them to
+specific files, hosts, or access methods.
+
+For faster small-size file transfers, @value{tramp} supports encoded
+transfers directly through the shell using @command{mimencode} or
+@command{uuencode} provided such tools are available on the remote
+host.
-@subsubheading Behind the scenes
+@subsubheading @value{tramp} behind the scenes
@cindex behind the scenes
@cindex details of operation
@cindex how it works
-This section tries to explain what goes on behind the scenes when you
-access a remote file through @value{tramp}.
+Accessing a remote file through @value{tramp} entails a series of
+actions, many of which are transparent to the user. Yet some actions
+may require user response (such as entering passwords or completing
+file names). One typical scenario, opening a file on a remote host, is
+presented here to illustrate the steps involved:
-Suppose you type @kbd{C-x C-f} and enter part of an @value{tramp} file name,
-then hit @kbd{@key{TAB}} for completion. Suppose further that this is
-the first time that @value{tramp} is invoked for the host in question. Here's
-what happens:
+@kbd{C-x C-f} to initiate find-file, enter part of the @value{tramp}
+file name, then hit @kbd{@key{TAB}} for completion. If this is the
+first time connection to that host, here's what happens:
@itemize
@item
-@value{tramp} discovers that it needs a connection to the host. So it
-invokes @samp{telnet @var{host}} or @samp{rsh @var{host} -l
-@var{user}} or a similar tool to connect to the remote host.
-Communication with this process happens through an
-@value{emacsname} buffer, that is, the output from the remote end
-goes into a buffer.
+@value{tramp} invokes @samp{telnet @var{host}} or @samp{rsh @var{host}
+-l @var{user}} and establishes an external process to connect to the
+remote host. @value{tramp} communicates with the process through an
+@value{emacsname} buffer, which also shows output from the remote
+host.
@item
-The remote host may prompt for a login name (for @command{telnet}).
-The login name is given in the file name, so @value{tramp} sends the
-login name and a newline.
+The remote host may prompt for a login name (for @command{telnet}, for
+example) in the buffer. If on the other hand, the login name was
+included in the file name portion, @value{tramp} sends the login name
+followed by a newline.
@item
-The remote host may prompt for a password or pass phrase (for
-@command{rsh} or for @command{telnet} after sending the login name).
-@value{tramp} displays the prompt in the minibuffer, asking you for the
-password or pass phrase.
-
-You enter the password or pass phrase. @value{tramp} sends it to the remote
-host, followed by a newline.
+The remote host may then prompt for a password or pass phrase (for
+@command{rsh} or for @command{telnet}). @value{tramp} displays the
+password prompt in the minibuffer. @value{tramp} then sends whatever
+is entered to the remote host, followed by a newline.
@item
-@value{tramp} now waits for the shell prompt or for a message that the login
-failed.
+@value{tramp} now waits for either the shell prompt or a failed login
+message.
-If @value{tramp} sees neither of them after a certain period of time
-(a minute, say), then it issues an error message saying that it
-couldn't find the remote shell prompt and shows you what the remote
-host has sent.
+If @value{tramp} does not receive any messages within a timeout period
+(a minute, for example), then @value{tramp} responds with an error
+message about not finding the remote shell prompt. If any messages
+from the remote host, @value{tramp} displays them in the buffer.
-If @value{tramp} sees a @samp{login failed} message, it tells you so,
-aborts the login attempt and allows you to try again.
+For any @samp{login failed} message from the remote host,
+@value{tramp} aborts the login attempt, and repeats the login steps
+again.
@item
-Suppose that the login was successful and @value{tramp} sees the shell prompt
-from the remote host. Now @value{tramp} invokes @command{/bin/sh} because
-Bourne shells and C shells have different command
-syntaxes.@footnote{Invoking @command{/bin/sh} will fail if your login
-shell doesn't recognize @samp{exec /bin/sh} as a valid command.
-Maybe you use the Scheme shell @command{scsh}@dots{}}
+Upon successful login and @value{tramp} recognizes the shell prompt
+from the remote host, @value{tramp} prepares the shell environment by
+turning off echoing, setting shell prompt, and other housekeeping
+chores.
-After the Bourne shell has come up, @value{tramp} sends a few commands to
-ensure a good working environment. It turns off echoing, it sets the
-shell prompt, and a few other things.
+@strong{Note} that for the remote shell, @value{tramp} invokes
+@command{/bin/sh}. The remote host must recognize @samp{exec /bin/sh}
+and execute the appropriate shell. This shell must support Bourne
+shell syntax.
@item
-Now the remote shell is up and it good working order. Remember, what
-was supposed to happen is that @value{tramp} tries to find out what files exist
-on the remote host so that it can do file name completion.
-
-So, @value{tramp} basically issues @command{cd} and @command{ls} commands and
-also sometimes @command{echo} with globbing. Another command that is
-often used is @command{test} to find out whether a file is writable or a
-directory or the like. The output of each command is parsed for the
-necessary operation.
+@value{tramp} executes @command{cd} and @command{ls} commands to find
+which files exist on the remote host. @value{tramp} sometimes uses
+@command{echo} with globbing. @value{tramp} checks if a file or
+directory is writable with @command{test}. After each command,
+@value{tramp} parses the output from the remote host for completing
+the next operation.
@item
-Suppose you are finished with file name completion, have entered @kbd{C-x
-C-f}, a full file name and hit @kbd{@key{RET}}. Now comes the time to
-transfer the file contents from the remote host to the local host so
-that you can edit them.
-
-See above for an explanation of how @value{tramp} transfers the file contents.
+After remote file name completion, @value{tramp} transfers the file
+contents from the remote host.
-For inline transfers, @value{tramp} issues a command like @samp{mimencode -b
-/path/to/remote/file}, waits until the output has accumulated in the
-buffer that's used for communication, then decodes that output to
-produce the file contents.
+For inline transfers, @value{tramp} sends a command, such as
+@samp{mimencode -b /path/to/remote/file}, waits until the output has
+accumulated in the buffer, decodes that output to produce the file's
+contents.
-For external transfers, @value{tramp} issues a command like the
-following:
+For external transfers, @value{tramp} sends a command as follows:
@example
rcp user@@host:/path/to/remote/file /tmp/tramp.4711
@end example
-It then reads the local temporary file @file{/tmp/tramp.4711} into a
-buffer and deletes the temporary file.
+@value{tramp} reads the local temporary file @file{/tmp/tramp.4711}
+into a buffer, and then deletes the temporary file.
@item
-You now edit the buffer contents, blithely unaware of what has happened
-behind the scenes. (Unless you have read this section, that is.) When
-you are finished, you type @kbd{C-x C-s} to save the buffer.
+Edit, modify, change the buffer contents as normal, and then save the
+buffer wth @kbd{C-x C-s}.
@item
-Again, @value{tramp} transfers the file contents to the remote host
-either inline or external. This is the reverse of what happens when
-reading the file.
+@value{tramp} transfers the buffer contents to the remote host in
+a reverse of the process using the appropriate inline or external
+program.
@end itemize
I hope this has provided you with a basic overview of what happens
@chapter Obtaining Tramp.
@cindex obtaining Tramp
-@value{tramp} is freely available on the Internet and the latest
-release may be downloaded from @uref{ftp://ftp.gnu.org/gnu/tramp/}.
-This release includes the full documentation and code for
-@value{tramp}, suitable for installation. But Emacs (22 or later)
-includes @value{tramp} already, and there is a @value{tramp} package
-for XEmacs, as well. So maybe it is easier to just use those. But if
-you want the bleeding edge, read on@dots{}
+@value{tramp} is included as part of Emacs (since Emacs version 22.1).
-For the especially brave, @value{tramp} is available from Git. The Git
-version is the latest version of the code and may contain incomplete
-features or new issues. Use these versions at your own risk.
+@value{tramp} is also freely packaged for download on the Internet at
+@uref{ftp://ftp.gnu.org/gnu/tramp/}.
-Instructions for obtaining the latest development version of @value{tramp}
-from Git can be found by going to the Savannah project page at the
-following URL and then clicking on the Git link in the navigation bar
-at the top.
+@value{tramp} development versions are available on Git servers.
+Development versions contain new and incomplete features.
+
+One way to obtain from Git server is to visit the Savannah project
+page at the following URL and then clicking on the Git link in the
+navigation bar at the top.
@noindent
@uref{http://savannah.gnu.org/projects/tramp/}
@noindent
-Or follow the example session below:
+Another way is to follow the terminal session below:
@example
] @strong{cd ~/@value{emacsdir}}
@end example
@noindent
-If you reside behind a firewall, you could use
+From behind a firewall:
@example
] @strong{git config --global http.proxy http://user:pwd@@proxy.server.com:8080}
@end example
@noindent
-Tramp developers use instead
+Tramp developers:
@example
] @strong{git clone login@@git.sv.gnu.org:/srv/git/tramp.git}
@end example
@noindent
-You should now have a directory @file{~/@value{emacsdir}/tramp}
-containing the latest version of @value{tramp}. You can fetch the latest
-updates from the repository by issuing the command:
+After one of the above commands, @file{~/@value{emacsdir}/tramp} will
+containing the latest version of @value{tramp}.
+
+@noindent
+To fetch updates from the repository, use git pull:
@example
] @strong{cd ~/@value{emacsdir}/tramp}
@end example
@noindent
-Once you've got updated files from the Git repository, you need to run
-@command{autoconf} in order to get an up-to-date @file{configure}
-script:
+Run @command{autoconf} as follows to generate an up-to-date
+@file{configure} script:
@example
] @strong{cd ~/@value{emacsdir}/tramp}
@cindex history
@cindex development history
-Development was started end of November 1998. The package was called
-@file{rssh.el}, back then. It only provided one method to access a
-file, using @command{ssh} to log in to a remote host and using
-@command{scp} to transfer the file contents. After a while, the name
-was changed to @file{rcp.el}, and now it's @value{tramp}. Along the way,
-many more methods for getting a remote shell and for transferring the
-file contents were added. Support for VC was added.
-
-After that, there were added the multi-hop methods in April 2000 and
-the unification of @value{tramp} and Ange-FTP file names in July 2002.
-In July 2004, multi-hop methods have been replaced by proxy hosts.
-Running commands on remote hosts was introduced in December 2005.
+@value{tramp} development started at the end of November 1998 as
+@file{rssh.el}. It provided only one method of access. It used
+@command{ssh} for login and @command{scp} to transfer file contents.
+The name was changed to @file{rcp.el} before it got its preset name
+@value{tramp}. New methods of remote access were added, so was support
+for version control.
+
+April 2000 was the first time when multi-hop methods were added. In
+July 2002, @value{tramp} unified file names with Ange-FTP@. In July
+2004, proxy hosts replaced multi-hop methods. Running commands on
+remote hosts was introduced in December 2005.
@ifset emacsgw
-Support of gateways exists since April 2007.
+Support for gateways since April 2007.
@end ifset
@ifset emacsgvfs
GVFS integration started in February 2009.
@end ifset
@ifset emacs
-Remote commands on Windows hosts are available since September 2011.
+Remote commands on Windows hosts since September 2011.
@end ifset
-Ad-hoc multi-hop methods (with a changed syntax) have been reenabled
-in November 2011. In November 2012, Juergen Hoetzel's
-@file{tramp-adb.el} has been added.
+Ad-hoc multi-hop methods (with a changed syntax) re-enabled in November
+2011.
-In December 2001, @value{tramp} has been added to the XEmacs package
-repository. Being part of the Emacs repository happened in June 2002,
-the first release including @value{tramp} was Emacs 22.1.
+In November 2012, added Juergen Hoetzel's @file{tramp-adb.el}.
-@value{tramp} is also a Debian GNU/Linux package since February 2001.
+In December 2001, XEmacs package repository adds @value{tramp}.
@c Installation chapter is necessary only in case of standalone
@node Configuration
-@chapter Configuring @value{tramp} for use
+@chapter Configuring @value{tramp}
@cindex configuration
-
@cindex default configuration
-@value{tramp} is (normally) fully functional when it is initially
-installed. It is initially configured to use the @command{scp}
-program to connect to the remote host. So in the easiest case, you
-just type @kbd{C-x C-f} and then enter the file name
-@file{@trampfn{, user, host, /path/to.file}}.
-
-On some hosts, there are problems with opening a connection. These are
-related to the behavior of the remote shell. See @xref{Remote shell
-setup}, for details on this.
-
-If you do not wish to use these commands to connect to the remote
-host, you should change the default connection and transfer method
-that @value{tramp} uses. There are several different methods that @value{tramp}
-can use to connect to remote hosts and transfer files
-(@pxref{Connection types}).
-
-If you don't know which method is right for you, see @xref{Default
-Method}.
-
-@strong{Note} that the following descriptions reference the setting of
-user options or variables, not all of which are autoloaded by
-@value{emacsname}. All examples assume that you have loaded
-@value{tramp} first:
+
+@value{tramp} is initially configured to use the @command{scp} program
+to connect to the remote host. Just type @kbd{C-x C-f} and then enter
+file name @file{@trampfn{, user, host, /path/to.file}}. For details,
+see @xref{Default Method}.
+
+For problems related to the behavior of remote shell, see @ref{Remote
+shell setup} for details.
+
+For changing the connection type and file access method from the
+defaults to one of several other options, see (@pxref{Connection
+types}).
+
+@strong{Note} that some user options and variables described in these
+examples are not auto loaded by @value{emacsname}. All examples
+require @value{tramp} is installed and loaded:
@lisp
(require 'tramp)
@menu
-* Connection types:: Types of connections made to remote hosts.
+* Connection types:: Types of connections to remote hosts.
* Inline methods:: Inline methods.
* External methods:: External methods.
@ifset emacsgvfs
@node Connection types
-@section Types of connections made to remote hosts
+@section Types of connections to remote hosts
@cindex connection types, overview
-There are two basic types of transfer methods, each with its own
-advantages and limitations. Both types of connection make use of a
-remote shell access program such as @command{rsh}, @command{ssh} or
-@command{telnet} to connect to the remote host.
-
-This connection is used to perform many of the operations that @value{tramp}
-requires to make the remote file system transparently accessible from
-the local host. It is only when visiting files that the methods
-differ.
+@dfn{Inline method} and @dfn{external method} are the two basic types
+of access methods. While they both use the same remote shell access
+programs, such as @command{rsh}, @command{ssh}, or @command{telnet},
+they differ in the file access methods. Choosing the right method
+becomes important for editing files, transferring large files, or
+operating on a large number of files.
@cindex inline methods
@cindex external methods
@cindex methods, inline
@cindex methods, external
-Loading or saving a remote file requires that the content of the file
-be transferred between the two hosts. The content of the file can
-be transferred using one of two methods: the @dfn{inline method} over
-the same connection used to log in to the remote host, or the
-@dfn{external method} through another connection using a remote copy
-program such as @command{rcp}, @command{scp} or @command{rsync}.
The performance of the external methods is generally better than that
of the inline methods, at least for large files. This is caused by
the need to encode and decode the data when transferring inline.
-The one exception to this rule are the @command{scp} based transfer
+The one exception to this rule are the @option{scp}-based access
methods. While these methods do see better performance when actually
transferring files, the overhead of the cryptographic negotiation at
startup may drown out the improvement in file transfer times.
@cindex inline methods
@cindex methods, inline
-The inline methods in @value{tramp} are quite powerful and can work in
-situations where you cannot use an external transfer program to
-connect. There are also strange inline methods which allow you to
-transfer files between @emph{user identities} rather than hosts, see
-below.
+Inline methods use the same login connection to transfer file
+contents. Inline methods are quick and easy for small files. They
+depend on the availability of suitable encoding and decoding programs
+on the remote host. For local source and destination, @value{tramp}
+may use built-in equivalents of such programs in @value{emacsname}.
-These methods depend on the existence of a suitable encoding and
-decoding command on remote host. Locally, @value{tramp} may be able to
-use features of @value{emacsname} to decode and encode the files or
-it may require access to external commands to perform that task.
+Inline methods can work in situations where an external transfer
+program is unavailable. Inline methods also work when transferring
+files between different @emph{user identities} on the same host.
@cindex uuencode
@cindex mimencode
@cindex base-64 encoding
-@value{tramp} checks the availability and usability of commands like
-@command{mimencode} (part of the @command{metamail} package) or
-@command{uuencode} on the remote host. The first reliable command
-will be used. The search path can be customized, see @ref{Remote
-programs}.
-If both commands aren't available on the remote host, @value{tramp}
-transfers a small piece of Perl code to the remote host, and tries to
-apply it for encoding and decoding.
+@value{tramp} checks the remote host for the availability and
+usability of @command{mimencode} (part of the @command{metamail}
+package) or @command{uuencode}. @value{tramp} uses the first reliable
+command it finds. @value{tramp}'s search path can be customized, see
+@ref{Remote programs}.
-The variable @var{tramp-inline-compress-start-size} controls, whether
-a file shall be compressed before encoding. This could increase
-transfer speed for large text files.
+In case both @command{mimencode} and @command{uuencode} are
+unavailable, @value{tramp} first transfers a small Perl program to the
+remote host, and then tries that program for encoding and decoding.
+To increase transfer speeds for large text files, use compression
+before encoding. The variable @var{tramp-inline-compress-start-size}
+specifies the file size for such optimization.
@table @asis
@item @option{rsh}
@cindex method rsh
@cindex rsh method
-Connect to the remote host with @command{rsh}. Due to the unsecure
-connection it is recommended for very local host topology only.
-
-On operating systems which provide the command @command{remsh} instead
-of @command{rsh}, you can use the method @option{remsh}. This is true
-for HP-UX or Cray UNICOS, for example.
+@command{rsh} is an option for connecting to hosts within local
+networks since @command{rsh} is not as secure as other methods.
@item @option{ssh}
@cindex method ssh
@cindex ssh method
-Connect to the remote host with @command{ssh}. This is identical to
-the previous option except that the @command{ssh} package is used,
-making the connection more secure.
-
-All the methods based on @command{ssh} have an additional feature: you
-can specify a host name which looks like @file{host#42} (the real host
-name, then a hash sign, then a port number). This means to connect to
-the given host but to also pass @code{-p 42} as arguments to the
-@command{ssh} command.
+@command{ssh} is a more secure option than others to connect to a
+remote host.
+@command{ssh} can also take extra parameters as port numbers. For
+example, a host on port 42 is specified as @file{host#42} (the real
+host name, a hash sign, then a port number). It is the same as passing
+@code{-p 42} to the @command{ssh} command.
@item @option{telnet}
@cindex method telnet
@cindex telnet method
-Connect to the remote host with @command{telnet}. This is as unsecure
+Connecting to a remote host with @command{telnet} is as insecure
as the @option{rsh} method.
@cindex method su
@cindex su method
-This method does not connect to a remote host at all, rather it uses
-the @command{su} program to allow you to edit files as another user.
-That means, the specified host name in the file name must be either
-@samp{localhost} or the host name as returned by the function
-@command{(system-name)}. For an exception of this rule see
-@ref{Multi-hops}.
-
+Instead of connecting to a remote host, @command{su} program allows
+editing as another user. The host can be either @samp{localhost} or
+the host returned by the function @command{(system-name)}. See
+@ref{Multi-hops} for an exception to this behavior.
@item @option{sudo}
@cindex method sudo
@cindex sudo method
-This is similar to the @option{su} method, but it uses @command{sudo}
-rather than @command{su} to become a different user.
-
-Note that @command{sudo} must be configured to allow you to start a
-shell as the user. It would be nice if it was sufficient if
-@command{ls} and @command{mimencode} were allowed, but that is not
-easy to implement, so I haven't got around to it, yet.
-
+Similar to @option{su} method, @option{sudo} uses @command{sudo}.
+@command{sudo} must have sufficient rights to start a shell.
@item @option{sshx}
@cindex method sshx
@cindex sshx method
-As you would expect, this is similar to @option{ssh}, only a little
-different. Whereas @option{ssh} opens a normal interactive shell on
-the remote host, this option uses @samp{ssh -t -t @var{host} -l
-@var{user} /bin/sh} to open a connection. This is useful for users
-where the normal login shell is set up to ask them a number of
-questions when logging in. This procedure avoids these questions, and
-just gives @value{tramp} a more-or-less ``standard'' login shell to work
-with.
-
-Note that this procedure does not eliminate questions asked by
-@command{ssh} itself. For example, @command{ssh} might ask ``Are you
-sure you want to continue connecting?'' if the host key of the remote
-host is not known. @value{tramp} does not know how to deal with such a
-question (yet), therefore you will need to make sure that you can log
-in without such questions.
+Works like @option{ssh} but without the extra authentication prompts.
+@option{sshx} uses @samp{ssh -t -t @var{host} -l @var{user} /bin/sh}
+to open a connection with a ``standard'' login shell.
-This is also useful for Windows users where @command{ssh}, when
-invoked from an @value{emacsname} buffer, tells them that it is not
-allocating a pseudo tty. When this happens, the login shell is wont
-to not print any shell prompt, which confuses @value{tramp} mightily.
+@strong{Note} that @option{sshx} does not bypass authentication
+questions. For example, if the host key of the remote host is not
+known, @option{sshx} will still ask ``Are you sure you want to
+continue connecting?''. @value{tramp} cannot handle such questions.
+Connections will have to be setup where logins can proceed without
+such questions.
-This supports the @samp{-p} argument.
+@option{sshx} is useful for Windows users when @command{ssh} triggers
+an error about allocating a pseudo tty. This happens due to missing
+shell prompts that confuses @value{tramp}.
+@option{sshx} supports the @samp{-p} argument.
@item @option{krlogin}
@cindex method krlogin
@cindex krlogin method
@cindex Kerberos (with krlogin method)
-This method is also similar to @option{ssh}. It only uses the
-@command{krlogin -x} command to log in to the remote host.
-
+This method is also similar to @option{ssh}. It uses the
+@command{krlogin -x} command only for remote host login.
@item @option{ksu}
@cindex method ksu
@cindex method plink
@cindex plink method
-This method is mostly interesting for Windows users using the PuTTY
+@option{plink} method is for Windows users with the PuTTY
implementation of SSH@. It uses @samp{plink -ssh} to log in to the
remote host.
-With a recent PuTTY, it is recommended to check the @samp{Share SSH
-connections if possible} control for that session.
+Check the @samp{Share SSH connections if possible} control for that
+session.
-This method supports the @samp{-P} argument.
+@option{plink} method supports the @samp{-P} argument.
@item @option{plinkx}
@cindex method plinkx
@cindex plinkx method
-Another method using PuTTY on Windows. Instead of host names, it
-expects PuTTY session names, calling @samp{plink -load @var{session}
--t}. User names and port numbers must be defined in the session.
+Another method using PuTTY on Windows with session names instead of
+host names. @option{plinkx} calls @samp{plink -load @var{session} -t}.
+User names and port numbers must be defined in the session.
-With a recent PuTTY, it is recommended to check the @samp{Share SSH
-connections if possible} control for that session.
+Check the @samp{Share SSH connections if possible} control for that
+session.
@end table
@cindex methods, external
@cindex external methods
-The external methods operate through multiple channels, using the
-remote shell connection for many actions while delegating file
-transfers to an external transfer utility.
+External methods operate over multiple channels, using the remote
+shell connection for some actions while delegating file transfers to
+an external transfer program.
-This saves the overhead of encoding and decoding that multiplexing the
-transfer through the one connection has with the inline methods.
+External methods save on the overhead of encoding and decoding of
+inline methods.
-Since external methods need their own overhead opening a new channel,
-all files which are smaller than @var{tramp-copy-size-limit} are still
-transferred with the corresponding inline method. It should provide a
-fair trade-off between both approaches.
+Since external methods have the overhead of opening a new channel,
+files smaller than @var{tramp-copy-size-limit} still use inline
+methods.
@table @asis
@item @option{rcp}---@command{rsh} and @command{rcp}
@cindex rcp (with rcp method)
@cindex rsh (with rcp method)
-This method uses the @command{rsh} and @command{rcp} commands to connect
-to the remote host and transfer files. This is probably the fastest
-connection method available.
+This method uses the @command{rsh} and @command{rcp} commands to
+connect to the remote host and transfer files. This is the fastest
+access method available.
The alternative method @option{remcp} uses the @command{remsh} and
-@command{rcp} commands. It should be applied on hosts where
-@command{remsh} is used instead of @command{rsh}.
-
+@command{rcp} commands.
@item @option{scp}---@command{ssh} and @command{scp}
@cindex method scp
@cindex scp (with scp method)
@cindex ssh (with scp method)
-Using @command{ssh} to connect to the remote host and @command{scp} to
-transfer files between the hosts is the best method for securely
-connecting to a remote host and accessing files.
-
-The performance of this option is also quite good. It may be slower than
-the inline methods when you often open and close small files however.
-The cost of the cryptographic handshake at the start of an @command{scp}
-session can begin to absorb the advantage that the lack of encoding and
-decoding presents.
-
-All the @command{ssh} based methods support the @samp{-p} feature
-where you can specify a port number to connect to in the host name.
-For example, the host name @file{host#42} tells @value{tramp} to
-specify @samp{-p 42} in the argument list for @command{ssh}, and to
-specify @samp{-P 42} in the argument list for @command{scp}.
+Using a combination of @command{ssh} to connect and @command{scp} to
+transfer is the most secure. While the performance is good, it is
+slower than the inline methods for smaller files. Though there is no
+overhead of encoding and decoding of the inline methods,
+@command{scp}'s cryptographic handshake negates those speed gains.
+@option{ssh}-based methods support @samp{-p} feature for specifying
+port numbers. For example, @file{host#42} passes @samp{-p 42} in the
+argument list to @command{ssh}, and @samp{-P 42} in the argument list
+to @command{scp}.
@item @option{rsync}---@command{ssh} and @command{rsync}
@cindex method rsync
@cindex rsync (with rsync method)
@cindex ssh (with rsync method)
-Using the @command{ssh} command to connect securely to the remote
-host and the @command{rsync} command to transfer files is almost
-identical to the @option{scp} method.
+@command{ssh} command to connect in combination with @command{rsync}
+command to transfer is similar to the @option{scp} method.
-While @command{rsync} performs much better than @command{scp} when
-transferring files that exist on both hosts, this advantage is lost if
-the file exists only on one side of the connection. A file can exists
-on both the remote and local host, when you copy a file from/to a
-remote host. When you just open a file from the remote host (or write
-a file there), a temporary file on the local side is kept as long as
-the corresponding buffer, visiting this file, is alive.
+@command{rsync} performs much better than @command{scp} when
+transferring files that exist on both hosts. However, this advantage
+is lost if the file exists only on one side of the connection.
This method supports the @samp{-p} argument.
@cindex scp (with scpx method)
@cindex ssh (with scpx method)
-As you would expect, this is similar to @option{scp}, only a little
-different. Whereas @option{scp} opens a normal interactive shell on
-the remote host, this option uses @samp{ssh -t -t @var{host} -l
-@var{user} /bin/sh} to open a connection. This is useful for users
-where the normal login shell is set up to ask them a number of
-questions when logging in. This procedure avoids these questions, and
-just gives @value{tramp} a more-or-less ``standard'' login shell to work
-with.
+@option{scpx} is useful to avoid login shell questions. It is similar
+in performance to @option{scp}. @option{scpx} uses @samp{ssh -t -t
+@var{host} -l @var{user} /bin/sh} to open a connection.
-This is also useful for Windows users where @command{ssh}, when
-invoked from an @value{emacsname} buffer, tells them that it is not
-allocating a pseudo tty. When this happens, the login shell is wont
-to not print any shell prompt, which confuses @value{tramp} mightily.
+@option{sshx} is useful for Windows users when @command{ssh} triggers
+an error about allocating a pseudo tty. This happens due to missing
+shell prompts that confuses @value{tramp}.
This method supports the @samp{-p} argument.
they use @command{pscp} or @command{psftp} for transferring the files.
These programs are part of PuTTY, an SSH implementation for Windows.
-With a recent PuTTY, it is recommended to configure the @samp{Share
-SSH connections if possible} control for that session.
+Check the @samp{Share SSH connections if possible} control for that
+session.
These methods support the @samp{-P} argument.
@cindex fsh (with fcp method)
@cindex fcp (with fcp method)
-This method is similar to @option{scp}, but it uses the @command{fsh}
-command to connect to the remote host, and it uses @command{fcp} for
-transferring the files. @command{fsh/fcp} are a front-end for
-@command{ssh} which allow for reusing the same @command{ssh} session
-for submitting several commands. This avoids the startup overhead of
-@command{scp} (which has to establish a secure connection whenever it
-is called). Note, however, that you can also use one of the inline
-methods to achieve a similar effect.
+This method is similar to @option{scp}, but uses @command{fsh} to
+connect and @command{fcp} to transfer files. @command{fsh/fcp}, a
+front-end for @command{ssh}, reuse @command{ssh} session by
+submitting several commands. This avoids the startup overhead due to
+@command{scp}'s secure connection. Inline methods have similar
+benefits.
-This method uses the command @samp{fsh @var{host} -l @var{user}
-/bin/sh -i} to establish the connection, it does not work to just say
-@command{fsh @var{host} -l @var{user}}.
+The command used for this connection is: @samp{fsh @var{host} -l
+@var{user} /bin/sh -i}
@cindex method fsh
@cindex fsh method
-There is no inline method using @command{fsh} as the multiplexing
-provided by the program is not very useful in our context. @value{tramp}
-opens just one connection to the remote host and then keeps it open,
-anyway.
-
+@option{fsh} has no inline method since the multiplexing it offers is
+not useful for @value{tramp}. @command{fsh} connects to remote host
+and @value{tramp} keeps that one connection open.
@item @option{nc}---@command{telnet} and @command{nc}
@cindex method nc
@cindex nc (with nc method)
@cindex telnet (with nc method)
-Using @command{telnet} to connect to the remote host and @command{nc}
-for file transfer is often the only possibility to access dumb
-devices, like routers or NAS hosts. Those hosts have just a
-restricted @command{busybox} as local shell, and there is no program
-to encode and decode files for transfer.
-
+Using @command{telnet} to connect and @command{nc} to transfer files
+is sometimes the only combination suitable for accessing routers or
+NAS hosts. These dumb devices have severely restricted local shells,
+such as the @command{busybox} and do not host any other encode or
+decode programs.
@item @option{ftp}
@cindex method ftp
@cindex ftp method
-This is not a native @value{tramp} method. Instead, it forwards all
-requests to @value{ftppackagename}.
+When @value{tramp} uses @option{ftp}, it forwards requests to whatever
+ftp program is specified by @value{ftppackagename}. This external
+program must be capable of servicing requests from @value{tramp}.
+
@ifset xemacs
-This works only for unified file names, see @ref{Issues}.
+This method works only for unified file names, see @ref{Issues}.
@end ifset
@cindex method smb
@cindex smb method
-This is another not native @value{tramp} method. It uses the
-@command{smbclient} command on different Unices in order to connect to
-an SMB server. An SMB server might be a Samba (or CIFS) server on
-another UNIX host or, more interesting, a host running MS Windows. So
-far, it is tested against MS Windows NT, MS Windows 2000, MS Windows
-XP, MS Windows Vista, and MS Windows 7.
-
-The first directory in the localname must be a share name on the remote
-host. Remember that the @code{$} character, in which default shares
-usually end, must be written @code{$$} due to environment variable
-substitution in file names. If no share name is given (i.e., remote
-directory @code{/}), all available shares are listed.
-
-Since authorization is done on share level, you will always be
-prompted for a password if you access another share on the same host.
-This can be suppressed by @ref{Password handling}.
-
-For authorization, MS Windows uses both a user name and a domain name.
-Because of this, the @value{tramp} syntax has been extended: you can
-specify a user name which looks like @code{user%domain} (the real user
-name, then a percent sign, then the domain name). So, to connect to
-the host @code{melancholia} as user @code{daniel} of the domain
-@code{BIZARRE}, and edit @file{.emacs} in the home directory (share
-@code{daniel$}) I would specify the file name @file{@trampfn{smb,
-daniel%BIZARRE, melancholia, /daniel$$/.emacs}}.
-
-Depending on the Windows domain configuration, a Windows user might be
-considered as domain user per default. In order to connect as local
-user, the WINS name of that host must be given as domain name.
-Usually, it is the host name in capital letters. In the example
-above, the local user @code{daniel} would be specified as
-@file{@trampfn{smb, daniel%MELANCHOLIA, melancholia, /daniel$$/.emacs}}.
-
-The domain name as well as the user name are optional. If no user
-name is specified at all, the anonymous user (without password
-prompting) is assumed. This is different from all other @value{tramp}
-methods, where in such a case the local user name is taken.
-
-The @option{smb} method supports the @samp{-p} argument.
-
-@strong{Please note:} If @value{emacsname} runs locally under MS
-Windows, this method isn't available. Instead, you can use UNC
-file names like @file{//melancholia/daniel$$/.emacs}. The only
-disadvantage is that there's no possibility to specify another user
-name.
+This is another non-native @value{tramp} method. @command{smbclient}
+connects to any host with SMB/CIFS protocol, such as MS Windows and
+Samba Servers running on Unixes. Tests show this @value{tramp} method
+works with MS Windows NT, MS Windows 2000, MS Windows XP, MS Windows
+Vista, and MS Windows 7.
+
+Using @command{smbclient} requires a few tweaks when working with
+@value{tramp}:
+
+The first directory in the localname must be a share name on the
+remote host.
+
+Since smb shares end in the @code{$} character, @value{tramp} must use
+@code{$$} when specifying those shares to avoid environment variable
+substitutions.
+
+When @value{tramp} is not specific about the share name or uses the
+generic remote directory @code{/}, @command{smbclient} returns all
+available shares.
+
+Since SMB authentication is based on each SMB share, @value{tramp}
+prompts for a password even when accessing a different share on the
+same SMB host. This prompting can be suppressed by @ref{Password
+handling}.
+
+To accommodate user name/domain name syntax required by MS Windows
+authorization, @value{tramp} provides for an extended syntax in
+@code{user%domain} format (where user is username, @code{%} is the
+percent symbol, and domain is the windows domain name). An example:
+
+@example
+@trampfn{smb, daniel%BIZARRE, melancholia, /daniel$$/.emacs}
+@end example
+
+where user @code{daniel} connects as a domain user to the SMB host
+@code{melancholia} in the windows domain @code{BIZARRE} to edit
+@file{.emacs} located in the home directory (share @code{daniel$}).
+
+Alternatively, for local WINS users (as opposed to domain users),
+substitute the domain name with the name of the local host in
+UPPERCASE as shown here:
+
+@example
+@trampfn{smb, daniel%MELANCHOLIA, melancholia, /daniel$$/.emacs}
+@end example
+
+where user @code{daniel} connects as local user to the SMB host
+@code{melancholia} in the local domain @code{MELANCHOLIA} to edit
+@file{.emacs} located in the home directory (share @code{daniel$}).
+
+The domain name and user name are optional for @command{smbclient}
+authentication. When user name is not specified, @command{smbclient}
+uses the anonymous user (without prompting for password). This
+behavior is unlike other @value{tramp} methods, where local user name
+is substituted.
+
+@option{smb} method is unavailable if @value{emacsname} is run under a
+local user authentication context in MS Windows. However such users
+can still access remote files using UNC file names instead of @value{tramp}:
+
+@example
+//melancholia/daniel$$/.emacs
+@end example
+
+UNC file name specification does not allow to specify a different user
+name for authentication like the @command{smbclient} can.
@item @option{adb}
@cindex method adb
@cindex adb method
-This special method uses the Android Debug Bridge for accessing
-Android devices. The Android Debug Bridge must be installed locally.
-Some GNU/Linux distributions offer it for installation, otherwise it
-can be installed as part of the Android SDK@. If the @command{adb}
-program is not found via the @env{PATH} environment variable, the
-variable @var{tramp-adb-program} must point to its absolute path.
-
-@value{tramp} does not connect Android devices to @command{adb},
-unless the custom option @option{tramp-adb-connect-if-not-connected}
-is non-@code{nil}. If there is exactly one Android device connected
-to @command{adb}, a host name is not needed in the remote file name.
-The default @value{tramp} name to be used is @file{@trampfn{adb, , ,}},
-therefore. Otherwise, one could find potential host names with the
-command @command{adb devices}.
-
-Usually, the @command{adb} method does not need any user name. It
-runs under the permissions of the @command{adbd} process on the
-Android device. If a user name is specified, @value{tramp} applies an
-@command{su} on the device. This does not work with all Android
-devices, especially with unrooted ones. In that case, an error
-message is displayed.
-
-If a device shall be connected via TCP/IP, it is possible to declare
-the port number to be used like @file{device#42}. Without a port
-number, the default value as declared in @command{adb} will be used.
-Port numbers are not applicable to Android devices connected via USB.
+This method uses Android Debug Bridge program for accessing Android
+devices. The Android Debug Bridge must be installed locally for
+@value{tramp} to work. Some GNU/Linux distributions provide Android
+Debug Bridge as an installation package. Alternatively, the program is
+installed as part of the Android SDK@. @value{tramp} finds the
+@command{adb} program either via the @env{PATH} environment variable
+or the absolute path set in the variable @var{tramp-adb-program}.
+
+@value{tramp} connects to Android devices with @option{adb} only when
+the custom option @option{tramp-adb-connect-if-not-connected} is not
+@code{nil}. Otherwise, the connection must be established outside
+@value{emacsname}.
+
+@value{tramp} does not require a host name part of the remote file
+name when a single Android device is connected to @command{adb}.
+@value{tramp} instead uses @file{@trampfn{adb, , ,}} as the default
+name. @command{adb devices} shows available host names.
+
+@option{adb} method normally does not need user name to authenticate
+on the Andriod device because it runs under the @command{adbd}
+process. But when a user name is specified, however, @value{tramp}
+applies an @command{su} in the syntax. When authentication does not
+succeed, especially on un-rooted Android devices, @value{tramp}
+displays login errors.
+
+For Andriod devices connected through TCP/IP, a port number can be
+specified using @file{device#42} host name syntax or @value{tramp} can
+use the default value as declared in @command{adb} command. Port
+numbers are not applicable to Android devices connected through USB@.
@end table
@cindex gvfs based methods
@cindex dbus
-The connection methods described in this section are based on GVFS
-@uref{http://en.wikipedia.org/wiki/GVFS}. Via GVFS, the remote
-filesystem is mounted locally through FUSE@. @value{tramp} uses
-this local mounted directory internally.
+GVFS is the virtual file system for the Gnome Desktop,
+@uref{http://en.wikipedia.org/wiki/GVFS}. Remote files on GVFS are
+mounted locally through FUSE and @value{tramp} uses this locally
+mounted directory internally.
-The communication with GVFS is implemented via D-Bus messages.
-Therefore, your @value{emacsname} must have D-Bus integration,
-@pxref{Top, , D-Bus, dbus}.
+@value{emacsname} uses the D-Bus mechanism to communicate with GVFS@.
+@value{emacsname} must have the message bus system, D-Bus integration
+active, @pxref{Top, , D-Bus, dbus}.
@table @asis
@item @option{afp}
@cindex method afp
@cindex afp method
-Access to Mac OS X volumes via the Apple Filing Protocol is offered by
-this method. The access must always be performed with a leading
-volume (share) name, like @file{@trampfn{afp, user, host, /volume}}.
-
-
+This method is for connecting to remote hosts with the Apple Filing
+Protocol for accessing files on Mac OS X volumes. @value{tramp} access
+syntax requires a leading volume (share) name, for example:
+@file{@trampfn{afp, user, host, /volume}}.
@item @option{dav}
+@item @option{davs}
@cindex method dav
@cindex method davs
@cindex dav method
@cindex davs method
-This method provides access to WebDAV files and directories. There
-exists also the external method @option{davs}, which uses SSL
-encryption for the access.
-
-Both methods support the port number specification as discussed above.
-
+@option{dav} method provides access to WebDAV files and directories
+based on standard protocols, such as HTTP@. @option{davs} does the same
+but with SSL encryption. Both methods support the port numbers.
@item @option{obex}
@cindex method obex
@cindex obex method
-OBEX is an FTP-like access protocol for simple devices, like cell
-phones. For the time being, @value{tramp} only supports OBEX over Bluetooth.
+OBEX is an FTP-like access protocol for cell phones and similar simple
+devices. @value{tramp} supports OBEX over Bluetooth.
@item @option{sftp}
@cindex method sftp
@cindex sftp method
-As you might expect, this method uses @command{sftp} in order to
-access the remote host. Contrary to the @option{ssh} and @option{scp}
-methods, it doesn't open an @command{ssh} session for login.
-Therefore, it could be used to access to remote hosts which refuse
-@command{ssh} for security reasons.
-
+This method uses @command{sftp} in order to securely access remote
+hosts. @command{sftp} is a more secure option for connecting to hosts
+that for security reasons refuse @command{ssh} connections.
@item @option{synce}
@cindex method synce
@cindex synce method
-The @option{synce} method allows communication with Windows Mobile
-devices. Beside GVFS for mounting remote files and directories via
-FUSE, it also needs the SYNCE-GVFS plugin.
+@option{synce} method allows connecting to Windows Mobile devices. It
+uses GVFS for mounting remote files and directories via FUSE and
+requires the SYNCE-GVFS plugin.
@end table
-@vindex tramp-gvfs-methods
@defopt tramp-gvfs-methods
-This custom option, a list, defines the external methods which shall
-be used with GVFS@. Per default, these are @option{afp},
-@option{dav}, @option{davs}, @option{obex}, @option{sftp} and
-@option{synce}. Other possible values are @option{ftp} and
-@option{smb}.
+@vindex tramp-gvfs-methods
+This custom option is a list of external methods for GVFS@. By
+default, this list includes @option{afp}, @option{dav}, @option{davs},
+@option{obex}, @option{sftp} and @option{synce}. Other methods to
+include are: @option{ftp} and @option{smb}.
@end defopt
@end ifset
@cindex methods, gateway
@cindex gateway methods
-Gateway methods are not methods to access a remote host directly.
-These methods are intended to pass firewalls or proxy servers.
-Therefore, they can be used for proxy host declarations
-(@pxref{Multi-hops}) only.
+Gateway methods are for proxy host declarations (@pxref{Multi-hops})
+so as to pass through firewalls and proxy servers. They are not like
+the other methods that declare direct connections to a remote host.
-A gateway method must always come along with a method which supports
-port setting. This is because @value{tramp} targets the accompanied
-method to @file{localhost#random_port}, from where the firewall or
-proxy server is accessed.
+A gateway method always comes with a port setting. @value{tramp}
+targets the port number with the gateway method
+@file{localhost#random_port} from where the firewall or proxy server
+is accessed.
-Gateway methods support user name and password declarations. These
-are used to authenticate towards the corresponding firewall or proxy
-server. They can be passed only if your friendly administrator has
-granted your access.
+Gateway methods support user name and password declarations for
+authenticating the corresponding firewall or proxy server. Such
+authentication can be passed through only if granted access by system
+administrators.
@table @asis
@item @option{tunnel}
@cindex tunnel method
This method implements an HTTP tunnel via the @command{CONNECT}
-command (see RFC 2616, 2817). Any HTTP 1.1 compliant (proxy) server
-shall support this command.
+command (conforming to RFC 2616, 2817 specifications). Proxy servers
+using HTTP version 1.1 or later protocol support this command.
-As authentication method, only @option{Basic Authentication} (see RFC
-2617) is implemented so far. If no port number is given in the
-declaration, port @option{8080} is used for the proxy server.
+For authentication, this protocol uses only @option{Basic
+Authentication} (see RFC 2617). When no port number is specified, this
+protocol defaults to @option{8080}.
@item @option{socks}
@cindex method socks
@cindex socks method
-The @command{socks} method provides access to SOCKSv5 servers (see
-RFC 1928). @option{Username/Password Authentication} according to RFC
-1929 is supported.
+The @option{socks} method connects to SOCKSv5 servers (see RFC 1928)
+and supports @option{Username/Password Authentication}.
-The default port number of the socks server is @option{1080}, if not
+The default port number for the socks server is @option{1080}, if not
specified otherwise.
@end table
@node Default Method
@section Selecting a default method
@cindex default method
-
@vindex tramp-default-method
-When you select an appropriate transfer method for your typical usage
-you should set the variable @code{tramp-default-method} to reflect that
-choice. This variable controls which method will be used when a method
-is not specified in the @value{tramp} file name. For example:
+@vindex tramp-default-method-alist
+
+Default method is for transferring files. The variable
+@code{tramp-default-method} sets it. @value{tramp} uses this variable
+to determine the default method for tramp file names that do not have
+one specified.
@lisp
(setq tramp-default-method "ssh")
@end lisp
-@vindex tramp-default-method-alist
-You can also specify different methods for certain user/host
-combinations, via the variable @code{tramp-default-method-alist}. For
-example, the following two lines specify to use the @option{ssh}
+Default methods for transferring files can be customized for specific
+user and host combinations through the alist variable
+@code{tramp-default-method-alist}.
+
+For example, the following two lines specify to use the @option{ssh}
method for all user names matching @samp{john} and the @option{rsync}
method for all host names matching @samp{lily}. The third line
specifies to use the @option{su} method for the user @samp{root} on
@noindent
See the documentation for the variable
-@code{tramp-default-method-alist} for more details.
+@code{tramp-default-method-alist} for details.
-External methods are normally preferable to inline methods, giving
-better performance.
+@noindent
+External methods performance faster for large files.
+@noindent
@xref{Inline methods}.
@xref{External methods}.
-Another consideration with the selection of transfer methods is the
-environment you will use them in and, especially when used over the
-Internet, the security implications of your preferred method.
+Choosing the access method also depends on the security environment.
+For example, @option{rsh} and @option{telnet} methods that use clear
+text password transfers are inappropriate for over the Internet
+connections. Secure remote connections should use @option{ssh} that
+provide encryption.
-The @option{rsh} and @option{telnet} methods send your password as
-plain text as you log in to the remote host, as well as
-transferring the files in such a way that the content can easily be
-read from other hosts.
-If you need to connect to remote systems that are accessible from the
-Internet, you should give serious thought to using @option{ssh} based
-methods to connect. These provide a much higher level of security,
-making it a non-trivial exercise for someone to obtain your password
-or read the content of the files you are editing.
+@subsection Which method to use?
+@cindex choosing the right method
+@value{tramp} provides maximum number of choices for maximum
+flexibility. Choosing which method depends on the hosts, clients,
+network speeds, and the security context.
-@subsection Which method is the right one for me?
-@cindex choosing the right method
+Start by using an inline method.
-Given all of the above, you are probably thinking that this is all fine
-and good, but it's not helping you to choose a method! Right you are.
-As a developer, we don't want to boss our users around but give them
-maximum freedom instead. However, the reality is that some users would
-like to have some guidance, so here I'll try to give you this guidance
-without bossing you around. You tell me whether it works @dots{}
-
-My suggestion is to use an inline method. For large files, external
-methods might be more efficient, but I guess that most people will
-want to edit mostly small files. And if you access large text files,
-compression (driven by @var{tramp-inline-compress-start-size}) shall
-still result in good performance.
-
-I guess that these days, most people can access a remote host by
-using @command{ssh}. So I suggest that you use the @option{ssh}
-method. So, type @kbd{C-x C-f @trampfn{ssh, root, otherhost,
-/etc/motd} @key{RET}} to edit the @file{/etc/motd} file on the other
-host.
+External methods might be more efficient for large files, but most
+@value{tramp} users edit small files more often than large files.
-If you can't use @option{ssh} to log in to the remote host, then
-select a method that uses a program that works. For instance, Windows
-users might like the @option{plink} method which uses the PuTTY
-implementation of @command{ssh}. Or you use Kerberos and thus like
-@option{krlogin}.
+Enable compression, @var{tramp-inline-compress-start-size}, for a
+performance boost for large files.
-For the special case of editing files on the local host as another
-user, see the @option{su} or @option{sudo} methods. They offer
-shortened syntax for the @samp{root} account, like
-@file{@trampfn{su, , , /etc/motd}}.
+Since @command{ssh} has become the most common method of remote host
+access and it has the most reasonable security protocols, use
+@option{ssh} method. Typical @option{ssh} usage to edit the
+@file{/etc/motd} file on the otherhost:
-People who edit large files may want to consider @option{scp} instead
-of @option{ssh}, or @option{pscp} instead of @option{plink}. These
-external methods are faster than inline methods for large files.
-Note, however, that external methods suffer from some limitations.
-Please try first whether you really get a noticeable speed advantage
-from using an external method! Maybe even for large files, inline
-methods are fast enough.
+@example
+@kbd{C-x C-f @trampfn{ssh, root, otherhost,/etc/motd} @key{RET}}
+@end example
+
+If @option{ssh} is unavailable for whatever reason, look for other
+obvious options. For Windows, try the @option{plink} method. For
+Kerberos, try @option{krlogin}.
+
+For editing local files as @option{su} or @option{sudo} methods, try
+the shortened syntax of @samp{root}:
+
+@example
+@kbd{C-x C-f @trampfn{su, , , /etc/motd} @key{RET}}
+@end example
+
+For editing large files, @option{scp} is faster than @option{ssh}.
+@option{pscp} is faster than @option{plink}. But this speed
+improvement is not always true.
@node Default User
@section Selecting a default user
@cindex default user
+@vindex tramp-default-user
+@vindex tramp-default-user-alist
-The user part of a @value{tramp} file name can be omitted. Usually,
-it is replaced by the user name you are logged in. Often, this is not
-what you want. A typical use of @value{tramp} might be to edit some
-files with root permissions on the local host. This case, you should
-set the variable @code{tramp-default-user} to reflect that choice.
+@value{tramp} file name can omit the user name part since
+@value{tramp} substitutes the currently logged-in user name. However
+this substitution can be overridden with @code{tramp-default-user}.
For example:
@lisp
(setq tramp-default-user "root")
@end lisp
-@code{tramp-default-user} is regarded as obsolete, and will be removed
-soon.
-
-@vindex tramp-default-user-alist
-You can also specify different users for certain method/host
-combinations, via the variable @code{tramp-default-user-alist}. For
-example, if you always have to use the user @samp{john} in the domain
-@samp{somewhere.else}, you can specify the following:
+Instead of a single default user, @code{tramp-default-user-alist}
+allows multiple default user values based on access method or host
+name combinations. The alist can hold multiple values. For example, to
+use the @samp{john} as the default user for the domain
+@samp{somewhere.else} only:
@lisp
(add-to-list 'tramp-default-user-alist
See the documentation for the variable @code{tramp-default-user-alist}
for more details.
-One trap to fall in must be known. If @value{tramp} finds a default
-user, this user will be passed always to the connection command as
-parameter (for example @command{ssh here.somewhere.else -l john}. If
-you have specified another user for your command in its configuration
-files, @value{tramp} cannot know it, and the remote access will fail.
-If you have specified in the given example in @file{~/.ssh/config} the
-lines
-
-@example
-Host here.somewhere.else
- User lily
-@end example
-
-@noindent
-than you must discard selecting a default user by @value{tramp}. This
-will be done by setting it to @code{nil} (or @samp{lily}, likewise):
+A Caution: @value{tramp} will override any default user specified in
+the configuration files outside @value{emacsname}, such as
+@file{~/.ssh/config}. To stop @value{tramp} from applying the default
+value, set the corresponding alist entry to nil:
@lisp
(add-to-list 'tramp-default-user-alist
'("ssh" "\\`here\\.somewhere\\.else\\'" nil))
@end lisp
-The last entry in @code{tramp-default-user-alist} could be your
-default user you'll apply predominantly. You shall @emph{append} it
-to that list at the end:
+The last entry in @code{tramp-default-user-alist} should be reserved
+for catch-all or most often used login.
@lisp
-(add-to-list 'tramp-default-user-alist '(nil nil "jonas") t)
+(add-to-list 'tramp-default-user-alist
+ '(nil nil "jonas") t)
@end lisp
@node Default Host
@section Selecting a default host
@cindex default host
-
@vindex tramp-default-host
-Finally, it is even possible to omit the host name part of a
-@value{tramp} file name. This case, the value of the variable
-@code{tramp-default-host} is used. Per default, it is initialized
-with the host name your local @value{emacsname} is running.
+@vindex tramp-default-host-alist
-If you, for example, use @value{tramp} mainly to contact the host
-@samp{target} as user @samp{john}, you can specify:
+When host name is omitted, @value{tramp} substitutes the value from
+the @code{tramp-default-host} variable. It is initially populated with
+the local hostname where @value{emacsname} is running. Both the
+default user and default host can be overridden as follows:
@lisp
(setq tramp-default-user "john"
tramp-default-host "target")
@end lisp
-Then the simple file name @samp{@trampfn{ssh, , ,}} will connect you
-to John's home directory on target.
+With both defaults set, @samp{@trampfn{ssh, , ,}} will connect
+@value{tramp} to John's home directory on target.
+
@ifset emacs
-Note, however, that the most simplification @samp{/::} won't work,
-because @samp{/:} is the prefix for quoted file names.
+@strong{Note} @samp{/::} won't work, because @samp{/:} is the prefix
+for quoted file names.
@end ifset
-@vindex tramp-default-host-alist
-Like with methods and users, you can also specify different default
-hosts for certain method/user combinations via the variable
-@code{tramp-default-host-alist}. Usually, this isn't necessary,
-because @code{tramp-default-host} should be sufficient. For some
-methods, like @option{adb}, that default value must be overwritten,
-which is already the initial value of @code{tramp-default-host-alist}.
+Instead of a single default host, @code{tramp-default-host-alist}
+allows multiple default host values based on access method or user
+name combinations. The alist can hold multiple values. While
+@code{tramp-default-host} is sufficient in most cases, some methods,
+like @option{adb}, require defaults overwritten.
@noindent
See the documentation for the variable @code{tramp-default-host-alist}
@cindex multi-hop
@cindex proxy hosts
-Sometimes, the methods described before are not sufficient.
-Sometimes, it is not possible to connect to a remote host using a
-simple command. For example, if you are in a secured network, you
-might have to log in to a bastion host first before you can connect to
-the outside world. Of course, the target host may also require a
-bastion host.
+Multi-hops are methods to reach hosts behind firewalls or to reach the
+outside world from inside a bastion host. With multi-hops,
+@value{tramp} can negotiate these hops with the appropriate user/host
+authentication at each hop. All methods until now have been the single
+hop kind, where the start and end points of the connection did not
+have intermediate check points.
-@vindex tramp-default-proxies-alist
@defopt tramp-default-proxies-alist
-In order to specify multiple hops, it is possible to define a proxy
-host to pass through, via the custom option
-@option{tramp-default-proxies-alist}. This variable keeps a list of
-triples (@var{host} @var{user} @var{proxy}).
-
-The first matching item specifies the proxy host to be passed for a
-file name located on a remote target matching @var{user}@@@var{host}.
-@var{host} and @var{user} are regular expressions or @code{nil}, which
-is interpreted as a regular expression which always matches.
-
-@var{proxy} must be a Tramp file name which localname part is ignored.
-Method and user name on @var{proxy} are optional, which is interpreted
-with the default values.
+@vindex tramp-default-proxies-alist
+@option{tramp-default-proxies-alist} specifies proxy hosts to pass
+through. This variable is list of triples consisting of (@var{host}
+@var{user} @var{proxy}).
+
+The first match is the proxy host through which passes the file name
+and the target host matching @var{user}@@@var{host}. @var{host} and
+@var{user} are regular expressions or @code{nil}, interpreted as a
+regular expression which always matches.
+
+@var{proxy} is a literal @value{tramp} file name whose local name part
+is ignored, and the method and user name parts are optional.
+
@ifset emacsgw
The method must be an inline or gateway method (@pxref{Inline
methods}, @pxref{Gateway methods}).
If @var{proxy} is @code{nil}, no additional hop is required reaching
@var{user}@@@var{host}.
-If you, for example, must pass the host @samp{bastion.your.domain} as
-user @samp{bird} for any remote host which is not located in your local
-domain, you can set
+For example, to pass through the host @samp{bastion.your.domain} as
+user @samp{bird} to reach remote hosts outside the local domain:
@lisp
(add-to-list 'tramp-default-proxies-alist
'("\\.your\\.domain\\'" nil nil))
@end lisp
-Please note the order of the code. @code{add-to-list} adds elements at the
-beginning of a list. Therefore, most relevant rules must be added last.
+@strong{Note}: @code{add-to-list} adds elements at the beginning of a
+list. Therefore, most relevant rules must come last in the list.
-Proxy hosts can be cascaded. If there is another host called
-@samp{jump.your.domain}, which is the only one in your local domain who
-is allowed connecting @samp{bastion.your.domain}, you can add another
-rule:
+Proxy hosts can be cascaded in the alist. If there is another host
+called @samp{jump.your.domain}, which is the only host allowed to
+connect to @samp{bastion.your.domain}, then:
@lisp
(add-to-list 'tramp-default-proxies-alist
"@trampfn{ssh, , jump.your.domain,}"))
@end lisp
-@var{proxy} can contain the patterns @code{%h} or @code{%u}. These
-patterns are replaced by the strings matching @var{host} or
-@var{user}, respectively.
+@var{proxy} can take patterns @code{%h} or @code{%u} for @var{host} or
+@var{user} respectively.
-If you, for example, wants to work as @samp{root} on hosts in the
-domain @samp{your.domain}, but login as @samp{root} is disabled for
-non-local access, you might add the following rule:
+To login as @samp{root} on remote hosts in the domain
+@samp{your.domain}, but login as @samp{root} is disabled for non-local
+access, then use this alist entry:
@lisp
(add-to-list 'tramp-default-proxies-alist
'("\\.your\\.domain\\'" "\\`root\\'" "@trampfn{ssh, , %h,}"))
@end lisp
-Opening @file{@trampfn{sudo, , randomhost.your.domain,}} would connect
-first @samp{randomhost.your.domain} via @code{ssh} under your account
-name, and perform @code{sudo -u root} on that host afterwards. It is
-important to know that the given method is applied on the host which
-has been reached so far. @code{sudo -u root}, applied on your local
-host, wouldn't be useful here.
+Opening @file{@trampfn{sudo, , randomhost.your.domain,}} first
+connects to @samp{randomhost.your.domain} via @code{ssh} under your
+account name, and then perform @code{sudo -u root} on that host.
-@var{host}, @var{user} and @var{proxy} can also be Lisp forms. These
-forms are evaluated, and must return a string, or @code{nil}. The
-previous example could be generalized then: For all hosts except my
-local one connect via @command{ssh} first, and apply @command{sudo -u
-root} afterwards:
+It is key for the sudo method in the above example to be applied on
+the host after reaching it and not on the local host.
+
+@var{host}, @var{user} and @var{proxy} can also take Lisp forms. These
+forms when evaluated must return either a string or @code{nil}.
+
+To generalize (from the previous example): For all hosts, except my
+local one, first connect via @command{ssh}, and then apply
+@command{sudo -u root}:
@lisp
(add-to-list 'tramp-default-proxies-alist
'((regexp-quote (system-name)) nil nil))
@end lisp
-This is the recommended configuration to work as @samp{root} on remote
-Ubuntu hosts.
+The above configuration allows @value{tramp} connection as @samp{root}
+to remote Ubuntu hosts.
@ifset emacsgw
-Finally, @code{tramp-default-proxies-alist} can be used to pass
-firewalls or proxy servers. Imagine your local network has a host
-@samp{proxy.your.domain} which is used on port 3128 as HTTP proxy to
-the outer world. Your friendly administrator has granted you access
-under your user name to @samp{host.other.domain} on that proxy
-server.@footnote{HTTP tunnels are intended for secure SSL/TLS
-communication. Therefore, many proxy server restrict the tunnels to
-related target ports. You might need to run your ssh server on your
-target host @samp{host.other.domain} on such a port, like 443 (https).
-See @uref{http://savannah.gnu.org/maintenance/CvsFromBehindFirewall}
-for discussion of ethical issues.} You would need to add the
-following rule:
+@code{tramp-default-proxies-alist} is also used for passing through
+firewalls or proxy servers.
+
+For example, the local host @samp{proxy.your.domain} on port 3128
+serves as HTTP proxy to the outer world. User has access rights to
+another proxy server on @samp{host.other.domain}.@footnote{HTTP tunnels
+are intended for secure SSL/TLS communication. Therefore, many proxy
+servers restrict the tunnels to related target ports. You might need
+to run your ssh server on your target host @samp{host.other.domain} on
+such a port, like 443 (https). See
+@uref{http://savannah.gnu.org/maintenance/CvsFromBehindFirewall} for
+discussion of ethical issues.} Then the configuration is:
@lisp
(add-to-list 'tramp-default-proxies-alist
'("\\`host\\.other\\.domain\\'" nil
- "@trampfn{tunnel, , proxy.your.domain#3128,}"))
+ "@trampfn{tunnel, , proxy.your.domain#3128,}"))
@end lisp
-Gateway methods can be declared as first hop only in a multiple hop
-chain.
+Gateway methods in a multiple hop chain can be declared only as the first hop.
@end ifset
@end defopt
-Hops to be passed tend to be restricted firewalls and alike.
-Sometimes they offer limited features only, like running @command{rbash}
-(restricted bash). This must be told to @value{tramp}.
+Passing through hops involves dealing with restricted shells, such as
+@command{rbash}. If @value{tramp} is made aware, then it would use
+them for proxies only.
-@vindex tramp-restricted-shell-hosts-alist
@defopt tramp-restricted-shell-hosts-alist
-This custom option keeps a list of regular expressions, which denote
-hosts running a registered shell like @command{rbash}. Those hosts
-can be used as proxies only.
+@vindex tramp-restricted-shell-hosts-alist
+An alist of regular expressions of hosts running restricted shells,
+such as @command{rbash}. @value{tramp} will then use them only as
+proxies.
-If the bastion host from the example above runs a restricted shell,
-you shall apply
+To specify the bastion host from the example above as running a
+restricted shell:
@lisp
(add-to-list 'tramp-restricted-shell-hosts-alist
@cindex using non-standard methods
@cindex create your own methods
-There is a variable @code{tramp-methods} which you can change if the
-predefined methods don't seem right.
-
-For the time being, I'll refer you to the Lisp documentation of that
-variable, accessible with @kbd{C-h v tramp-methods @key{RET}}.
+The @code{tramp-methods} variable currently has an exhaustive list of
+predefined methods. Any part of this list can be modified with more
+suitable settings. Refer to the Lisp documentation of that variable,
+accessible with @kbd{C-h v tramp-methods @key{RET}}.
@node Customizing Completion
@cindex selecting config files
@vindex tramp-completion-function-alist
-The variable @code{tramp-completion-function-alist} is intended to
-customize which files are taken into account for user and host name
-completion (@pxref{File name completion}). For every method, it keeps
-a set of configuration files, accompanied by a Lisp function able to
-parse that file. Entries in @code{tramp-completion-function-alist}
-have the form (@var{method} @var{pair1} @var{pair2} @dots{}).
+@code{tramp-completion-function-alist} uses predefined files for user
+and host name completion (@pxref{File name completion}). For each
+method, it keeps a set of configuration files and a function that can
+parse that file. Each entry in @code{tramp-completion-function-alist}
+is of the form (@var{method} @var{pair1} @var{pair2} @dots{}).
Each @var{pair} is composed of (@var{function} @var{file}).
-@var{function} is responsible to extract user names and host names
+@var{function} is responsible for extracting user names and host names
from @var{file} for completion. There are two functions which access
this variable:
@item @code{tramp-parse-hosts}
@findex tramp-parse-hosts
-A function dedicated to @file{/etc/hosts} style files. It returns
-host names only.
+A function dedicated to @file{/etc/hosts} for host names.
@item @code{tramp-parse-passwd}
@findex tramp-parse-passwd
-A function which parses @file{/etc/passwd} like files. Obviously, it
-can return user names only.
+A function which parses @file{/etc/passwd} files for user names.
@item @code{tramp-parse-netrc}
@findex tramp-parse-netrc
-Finally, a function which parses @file{~/.netrc} like files. This
-includes also @file{~/.authinfo}-style files.
+A function which parses @file{~/.netrc} and @file{~/.authinfo}-style files.
@end table
-If you want to keep your own data in a file, with your own structure,
-you might provide such a function as well. This function must meet
-the following conventions:
+To keep a custom file with custom data in a custom structure, a custom
+function has to be provided. This function must meet the following
+conventions:
@defun my-tramp-parse file
-@var{file} must be either a file name on your host, or @code{nil}.
-The function must return a list of (@var{user} @var{host}), which are
-taken as candidates for user and host name completion.
+@var{file} must be either a file on the host, or @code{nil}. The
+function must return a list of (@var{user} @var{host}), which are
+taken as candidates for completion for user and host names.
Example:
@example
@section Reusing passwords for several connections
@cindex passwords
-Sometimes it is necessary to connect to the same remote host several
-times. Reentering passwords again and again would be annoying, when
-the chosen method does not support access without password prompt
-through own configuration.
-
-The best recommendation is to use the method's own mechanism for
-password handling. Consider @command{ssh-agent} for @option{ssh}-like
+To avoid repeated prompts for passwords, consider native caching
+mechanisms, such as @command{ssh-agent} for @option{ssh}-like
methods, or @command{pageant} for @option{plink}-like methods.
-However, if you cannot apply such native password handling,
-@value{tramp} offers alternatives.
+@value{tramp} offers alternatives when native solutions cannot meet
+the need.
@anchor{Using an authentication file}
@subsection Using an authentication file
-
@vindex auth-sources
-The package @file{auth-source.el}, originally developed in No Gnus,
-offers the possibility to read passwords from a file, like FTP does it
-from @file{~/.netrc}. The default authentication file is
-@file{~/.authinfo.gpg}, this can be changed via the variable
+
+The package @file{auth-source.el}, originally developed for No Gnus,
+reads passwords from different sources, @xref{Help for users, ,
+auth-source, auth}. The default authentication file is
+@file{~/.authinfo.gpg}, but this can be changed via the variable
@code{auth-sources}.
@noindent
-A typical entry in the authentication file would be
+A typical entry in the authentication file:
@example
machine melancholia port scp login daniel password geheim
@end example
-The port can be any @value{tramp} method (@pxref{Inline methods},
-@pxref{External methods}), to match only this method. When you omit
-the port, you match all @value{tramp} methods.
+The port can take any @value{tramp} method (@pxref{Inline methods},
+@pxref{External methods}). Omitting port values matches all
+@value{tramp} methods.
-In case of problems, setting @code{auth-source-debug} to @code{t}
-gives useful debug messages.
+Setting @code{auth-source-debug} to @code{t} to debug messages.
@anchor{Caching passwords}
@subsection Caching passwords
-If there is no authentication file, @value{tramp} caches the passwords
-entered by you. They will be reused next time if a connection needs
-them for the same user name and host name, independently of the
-connection method.
+@value{tramp} can cache passwords as entered and reuse when needed for
+the same user or host name independent of the access method.
@vindex password-cache-expiry
-Passwords are not saved permanently, that means the password caching
-is limited to the lifetime of your @value{emacsname} session. You
-can influence the lifetime of password caching by customizing the
-variable @code{password-cache-expiry}. The value is the number of
-seconds how long passwords are cached. Setting it to @code{nil}
-disables the expiration.
+
+@code{password-cache-expiry} sets the duration (in seconds) the
+passwords are remembered. Passwords are never saved permanently nor
+can they extend beyond the lifetime of the current @value{emacsname}
+session. Set @code{password-cache-expiry} to @code{nil} to disable
+expiration.
@vindex password-cache
-If you don't like this feature for security reasons, password caching
-can be disabled totally by customizing the variable
-@code{password-cache} (setting it to @code{nil}).
-Implementation Note: password caching is based on the package
-@file{password-cache.el}. For the time being, it is activated only
-when this package is seen in the @code{load-path} while loading
-@value{tramp}.
+Set @code{password-cache} to @code{nil} to disable password caching.
+
+@strong{Implementation Note}: password caching depends on
+@file{password-cache.el} package. @value{tramp} activates password
+caching only if @value{tramp} can discover, while @value{emacsname} is
+loading, the package through @code{load-path}.
+
@ifset installchapter
-If you don't use No Gnus, you can take @file{password.el} from the
-@value{tramp} @file{contrib} directory, see @ref{Installation
-parameters}.
+@file{password.el} is available from No Gnus or from the @value{tramp}
+@file{contrib} directory, see @ref{Installation parameters}.
@end ifset
@node Connection caching
@section Reusing connection related information
@cindex caching
-
@vindex tramp-persistency-file-name
-In order to reduce initial connection time, @value{tramp} stores
-connection related information persistently. The variable
-@code{tramp-persistency-file-name} keeps the file name where these
-information are written. Its default value is
+
+For faster initial connection times, @value{tramp} stores previous
+connection properties in a file specified by the variable
+@code{tramp-persistency-file-name}.
+
+The default file name for @code{tramp-persistency-file-name} is:
@ifset emacs
@file{~/.emacs.d/tramp}.
@end ifset
@ifset xemacs
@file{~/.xemacs/tramp}.
@end ifset
-It is recommended to choose a local file name.
-
-@value{tramp} reads this file during startup, and writes it when
-exiting @value{emacsname}. You can simply remove this file if
-@value{tramp} shall be urged to recompute these information next
-@value{emacsname} startup time.
-
-Using such persistent information can be disabled by setting
-@code{tramp-persistency-file-name} to @code{nil}.
-
-Once consequence of reusing connection related information is that
-@value{tramp} needs to distinguish hosts. If you, for example, run a
-local @code{sshd} on port 3001, which tunnels @command{ssh} to another
-host, you could access both @file{@trampfn{ssh, , localhost,}} and
-@file{@trampfn{ssh, , localhost#3001,}}. @value{tramp} would use the
-same host related information (like paths, Perl variants, etc) for
-both connections, although the information is valid only for one of
-them.
-In order to avoid trouble, you must use another host name for one of
-the connections, like introducing a @option{Host} section in
-@file{~/.ssh/config} (@pxref{Frequently Asked Questions}) or applying
-multiple hops (@pxref{Multi-hops}).
+@value{tramp} reads this file during @value{emacsname} startup, and
+writes to it when exiting @value{emacsname}. Delete this file for
+@value{tramp} to recreate a new one on next @value{emacsname} startup.
+
+Set @code{tramp-persistency-file-name} to @code{nil} to disable
+storing connections persistently.
-When @value{tramp} detects a changed operating system version on a
-remote host (via the command @command{uname -sr}), it flushes all
-connection related information for this host, and opens the
-connection again.
+To reuse connection information from the persistent list,
+@value{tramp} needs to uniquely identify every host. However in some
+cases, two different connections may result in the same persistent
+information. For example, connecting to a host using @command{ssh} and
+connecting to the same host through @code{sshd} on port 3001. Both
+access methods result in nearly identical persistent specifications
+@file{@trampfn{ssh, , localhost,}} and @file{@trampfn{ssh, ,
+localhost#3001,}}.
+
+Changing host names could avoid duplicates. One way is to add a
+@option{Host} section in @file{~/.ssh/config} (@pxref{Frequently Asked
+Questions}). Another way is to apply multiple hops (@pxref{Multi-hops}).
+
+When @value{tramp} detects a change in the operating system version in
+a remote host (via the command @command{uname -sr}), it flushes all
+connection related information for that host and creates a new entry.
@node Predefined connection information
@section Setting own connection related information
+@vindex tramp-connection-properties
-Sometimes, method specific arguments in @code{tramp-methods} do not
-fit your needs. Sometimes, @value{tramp} is not able to detect
-correct connection related information. In such cases, you could tell
-@value{tramp} which value it has to take. Since this could result in
-errors, it has to be used with care.
+For more precise customization, parameters specified by
+@code{tramp-methods} can be overwritten manually.
-@vindex tramp-connection-properties
-Such settings can be performed via the list
-@code{tramp-connection-properties}. An entry in this list has the
-form @code{(@var{regexp} @var{property} @var{value})}. @var{regexp}
-matches remote file names for which a property shall be predefined.
-It can be @code{nil}. @var{property} is a string, and @var{value} the
-corresponding value.
-
-@var{property} could be any method specific parameter found in
-@code{tramp-methods}. The parameter key in @code{tramp-methods} is a
-symbol name @code{tramp-<foo>}. In order to overwrite it,
-@var{property} must be the string @samp{<foo>}. If you, for example,
-want to change the remote shell to be used on a remote machine, you
-could apply
+Set @code{tramp-connection-properties} to manually override
+@code{tramp-methods}. Properties in this list are in the form
+@code{(@var{regexp} @var{property} @var{value})}. @var{regexp} matches
+remote file names. Use @code{nil} to match all. @var{property} is the
+property's name, and @var{value} is the property's value.
+
+@var{property} is any method specific parameter contained in
+@code{tramp-methods}. The parameter key in @code{tramp-methods} is a
+symbol name @code{tramp-<foo>}. To overwrite that property, use the
+string @samp{<foo>} for @var{property}. For example, this changes the
+remote shell:
@lisp
(add-to-list 'tramp-connection-properties
"remote-shell-login" '("-")))
@end lisp
-This would overwrite the @code{tramp-remote-shell} and
-@code{tramp-remote-shell-login} parameters in @code{tramp-methods}, to
-be used on that remote host.
+The parameters @code{tramp-remote-shell} and
+@code{tramp-remote-shell-login} in @code{tramp-methods} now have new
+values for the remote host.
-@var{property} could also be any property found in the file
+@var{property} could also be any property found in
@code{tramp-persistency-file-name}.
-A special property is @samp{busybox}. This must be set, if the remote
-host runs a very restricted busybox as shell, which closes the
-connection at will. Since there is no reliable test for this,
-@value{tramp} must be indicated this way. Example:
+To get around how restricted shells randomly drop connections, set the
+special property @samp{busybox}. For example:
@lisp
(add-to-list 'tramp-connection-properties
@node Remote programs
@section How @value{tramp} finds and uses programs on the remote host
-@value{tramp} depends on a number of programs on the remote host in order to
-function, including @command{ls}, @command{test}, @command{find} and
+@value{tramp} requires access to and rights to several commands on
+remote hosts: @command{ls}, @command{test}, @command{find} and
@command{cat}.
-In addition to these required tools, there are various tools that may be
-required based on the connection method. See @ref{Inline methods} and
-@ref{External methods} for details on these.
+Besides there are other required programs for @ref{Inline methods} and
+@ref{External methods} of connection.
-Certain other tools, such as @command{perl} (or @command{perl5}) and
-@command{grep} will be used if they can be found. When they are
-available, they are used to improve the performance and accuracy of
-remote file access.
+To improve performance and accuracy of remote file access,
+@value{tramp} uses @command{perl} (or @command{perl5}) and
+@command{grep} when available.
+@defopt tramp-remote-path
@vindex tramp-remote-path
@vindex tramp-default-remote-path
@vindex tramp-own-remote-path
-@defopt tramp-remote-path
-When @value{tramp} connects to the remote host, it searches for the
-programs that it can use. The custom option
-@option{tramp-remote-path} controls the directories searched on the
-remote host.
+@option{tramp-remote-path} specifies which remote directory paths
+@value{tramp} can search for @ref{Remote programs}.
-By default, this is set to a reasonable set of defaults for most
-hosts. The symbol @code{tramp-default-remote-path} is a place
-holder, it is replaced by the list of directories received via the
-command @command{getconf PATH} on your remote host. For example,
-on Debian GNU/Linux this is @file{/bin:/usr/bin}, whereas on Solaris
-this is @file{/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:/opt/SUNWspro/bin}.
-It is recommended to apply this symbol on top of
-@option{tramp-remote-path}.
+@value{tramp} uses standard defaults, such as @file{/bin} and
+@file{/usr/bin}, which are reasonable for most hosts. To accommodate
+differences in hosts and paths, for example, @file{/bin:/usr/bin} on
+Debian GNU/Linux or
+@file{/usr/xpg4/bin:/usr/ccs/bin:/usr/bin:/opt/SUNWspro/bin} on
+Solaris, @value{tramp} queries the remote host with @command{getconf
+PATH} and updates the symbol @code{tramp-default-remote-path}.
-It is possible, however, that your local (or remote ;) system
-administrator has put the tools you want in some obscure local
-directory.
-
-In this case, you can still use them with @value{tramp}. You simply
-need to add code to your @file{.emacs} to add the directory to the
-remote path. This will then be searched by @value{tramp} when you
-connect and the software found.
-
-To add a directory to the remote search path, you could use code such
-as:
+For instances where hosts keep obscure locations for paths for
+security reasons, manually add such paths to local @file{.emacs} as
+shown below for @value{tramp} to use when connecting.
@lisp
(add-to-list 'tramp-remote-path "/usr/local/perl/bin")
@end lisp
-Another possibility is to reuse the path settings of your remote
-account when you log in. Usually, these settings are overwritten,
-because they might not be useful for @value{tramp}. The place holder
-@code{tramp-own-remote-path} preserves these settings. You can
-activate it via
+Another way to find the remote path is to use the path assigned to the
+remote user by the remote host. @value{tramp} does not normally retain
+this remote path after logging. However, @code{tramp-own-remote-path}
+preserves the path value, which can be used to update
+@code{tramp-remote-path}.
@lisp
(add-to-list 'tramp-remote-path 'tramp-own-remote-path)
@end lisp
@end defopt
-@value{tramp} caches several information, like the Perl binary
-location. The changed remote search path wouldn't affect these
-settings. In order to force @value{tramp} to recompute these values,
-you must exit @value{emacsname}, remove your persistency file
-(@pxref{Connection caching}), and restart @value{emacsname}.
+When remote search paths are changed, local @value{tramp} caches must
+be recomputed. To force @value{tramp} to recompute afresh, exit
+@value{emacsname}, remove the persistent file (@pxref{Connection
+caching}), and restart @value{emacsname}.
@node Remote shell setup
@cindex @file{.login} file
@cindex shell init files
-As explained in the @ref{Overview} section, @value{tramp} connects to the
-remote host and talks to the shell it finds there. Of course, when you
-log in, the shell executes its init files. Suppose your init file
-requires you to enter the birth date of your mother; clearly @value{tramp}
-does not know this and hence fails to log you in to that host.
-
-There are different possible strategies for pursuing this problem. One
-strategy is to enable @value{tramp} to deal with all possible situations.
-This is a losing battle, since it is not possible to deal with
-@emph{all} situations. The other strategy is to require you to set up
-the remote host such that it behaves like @value{tramp} expects. This might
-be inconvenient because you have to invest a lot of effort into shell
-setup before you can begin to use @value{tramp}.
-
-The package, therefore, pursues a combined approach. It tries to
-figure out some of the more common setups, and only requires you to
-avoid really exotic stuff. For example, it looks through a list of
-directories to find some programs on the remote host. And also, it
-knows that it is not obvious how to check whether a file exists, and
-therefore it tries different possibilities. (On some hosts and
-shells, the command @command{test -e} does the trick, on some hosts
-the shell builtin doesn't work but the program @command{/usr/bin/test
--e} or @command{/bin/test -e} works. And on still other hosts,
-@command{ls -d} is the right way to do this.)
-
-Below you find a discussion of a few things that @value{tramp} does not deal
-with, and that you therefore have to set up correctly.
+@value{tramp} checks for the availability of standard programs in the
+usual locations. Common tactics include successively trying
+@command{test -e}, @command{/usr/bin/test -e}, and @command{/bin/test
+-e}. @command{ls -d} is another approach. But these approaches do not
+help with these new login patterns.
-@table @asis
-@item @var{shell-prompt-pattern}
-@vindex shell-prompt-pattern
-
-After logging in to the remote host, @value{tramp} has to wait for the remote
-shell startup to finish before it can send commands to the remote
-shell. The strategy here is to wait for the shell prompt. In order to
-recognize the shell prompt, the variable @code{shell-prompt-pattern} has
-to be set correctly to recognize the shell prompt on the remote host.
-
-Note that @value{tramp} requires the match for @code{shell-prompt-pattern}
-to be at the end of the buffer. Many people have something like the
-following as the value for the variable: @samp{^[^>$][>$] *}. Now
-suppose your shell prompt is @code{a <b> c $ }. In this case,
-@value{tramp} recognizes the @code{>} character as the end of the prompt,
-but it is not at the end of the buffer.
+When @value{tramp} encounters two-factor logins or additional challenge
+questions, such as entering birth date or security code or passphrase,
+@value{tramp} needs a few more configuration steps to accommodate
+them.
+The difference between a password prompt and a passphrase prompt is
+that the password for completing the login while the passphrase is
+for authorizing access to local authentication information, such as
+the ssh key.
+
+There is no one configuration to accommodate all the variations in
+login security, especially not the exotic ones. However, @value{tramp}
+provides a few tweaks to address the most common ones.
+
+@table @asis
@item @var{tramp-shell-prompt-pattern}
@vindex tramp-shell-prompt-pattern
-This regular expression is used by @value{tramp} in the same way as
-@code{shell-prompt-pattern}, to match prompts from the remote shell.
-This second variable exists because the prompt from the remote shell
-might be different from the prompt from a local shell---after all,
-the whole point of @value{tramp} is to log in to remote hosts as a
-different user. The default value of
-@code{tramp-shell-prompt-pattern} is the same as the default value of
-@code{shell-prompt-pattern}, which is reported to work well in many
-circumstances.
+@code{tramp-shell-prompt-pattern} is for remote login shell prompt,
+which may not be the same as the local login shell prompt,
+@code{shell-prompt-pattern}. Since most hosts use identical prompts,
+@value{tramp} sets a similar default value for both prompts.
@item @var{tramp-password-prompt-regexp}
+@item @var{tramp-wrong-passwd-regexp}
@vindex tramp-password-prompt-regexp
@vindex tramp-wrong-passwd-regexp
-During login, @value{tramp} might be forced to enter a password or a
-passphrase. The difference between both is that a password is
-requested from the shell on the remote host, while a passphrase is
-needed for accessing local authentication information, like your ssh
-key.
-
-@var{tramp-password-prompt-regexp} handles the detection of such
-requests for English environments. When you use another localization
-of your (local or remote) host, you might need to adapt this. Example:
+@value{tramp} uses @var{tramp-password-prompt-regexp} to distinguish
+between prompts for passwords and prompts for passphrases. By default,
+@var{tramp-password-prompt-regexp} handles the detection in English
+language environments. See a localization example below:
@lisp
(setq
".*:\0? *"))
@end lisp
-In parallel, it might also be necessary to adapt
-@var{tramp-wrong-passwd-regexp}.
+Similar localization may be necessary for handling wrong password
+prompts, for which @value{tramp} uses @var{tramp-wrong-passwd-regexp}.
@item @command{tset} and other questions
@cindex Unix command tset
@cindex tset Unix command
+@vindex tramp-terminal-type
-Some people invoke the @command{tset} program from their shell startup
-scripts which asks the user about the terminal type of the shell.
-Maybe some shells ask other questions when they are started.
-@value{tramp} does not know how to answer these questions. There are
-two approaches for dealing with this problem. One approach is to take
-care that the shell does not ask any questions when invoked from
-@value{tramp}. You can do this by checking the @env{TERM}
-environment variable, it will be set to @code{dumb} when connecting.
+To suppress inappropriate prompts for terminal type, @value{tramp}
+sets the @env{TERM} to @code{dumb} before the remote login process
+begins via the variable @code{tramp-terminal-type}. This will silence
+common @command{tset} related prompts.
-@vindex tramp-terminal-type
-The variable @code{tramp-terminal-type} can be used to change this value
-to @code{dumb}.
+@value{tramp}'s strategy for handling such prompts (commonly triggered
+from login scripts on remote hosts) is to set the environment
+variables so that no prompts interrupt the shell initialization
+process.
@vindex tramp-actions-before-shell
-The other approach is to teach @value{tramp} about these questions. See
-the variable @code{tramp-actions-before-shell}. Example:
+
+An alternative approach is to configure @value{tramp} with strings
+that can identify such questions using
+@code{tramp-actions-before-shell}. Example:
@lisp
(defconst my-tramp-prompt-regexp
@end lisp
-@item Environment variables named like users in @file{.profile}
+@item Conflicting names for users and variables in @file{.profile}
-If you have a user named frumple and set the variable @env{FRUMPLE} in
-your shell environment, then this might cause trouble. Maybe rename
-the variable to @env{FRUMPLE_DIR} or the like.
-
-This weird effect was actually reported by a @value{tramp} user!
+When a user name is the same as a variable name in a local file, such
+as @file{.profile}, then @value{tramp} may send incorrect values for
+environment variables. To avoid incorrect values, change the local
+variable name to something different from the user name. For example,
+if the user name is @env{FRUMPLE}, then change the variable name to
+@env{FRUMPLE_DIR}.
@item Non-Bourne commands in @file{.profile}
-After logging in to the remote host, @value{tramp} issues the command
-@command{exec /bin/sh}. (Actually, the command is slightly
-different.) When @command{/bin/sh} is executed, it reads some init
-files, such as @file{~/.shrc} or @file{~/.profile}.
-
-Now, some people have a login shell which is not @code{/bin/sh} but a
-Bourne-ish shell such as bash or ksh. Some of these people might put
-their shell setup into the files @file{~/.shrc} or @file{~/.profile}.
-This way, it is possible for non-Bourne constructs to end up in those
-files. Then, @command{exec /bin/sh} might cause the Bourne shell to
-barf on those constructs.
-
-As an example, imagine somebody putting @command{export FOO=bar} into
-the file @file{~/.profile}. The standard Bourne shell does not
-understand this syntax and will emit a syntax error when it reaches
-this line.
-
-Another example is the tilde (@code{~}) character, say when adding
-@file{~/bin} to @env{PATH}. Many Bourne shells will not expand this
-character, and since there is usually no directory whose name consists
-of the single character tilde, strange things will happen.
-
-What can you do about this?
-
-Well, one possibility is to make sure that everything in
-@file{~/.shrc} and @file{~/.profile} on all remote hosts is
-Bourne-compatible. In the above example, instead of @command{export
-FOO=bar}, you might use @command{FOO=bar; export FOO} instead.
-
-The other possibility is to put your non-Bourne shell setup into some
-other files. For example, bash reads the file @file{~/.bash_profile}
-instead of @file{~/.profile}, if the former exists. So bash
-aficionados just rename their @file{~/.profile} to
-@file{~/.bash_profile} on all remote hosts, and Bob's your uncle.
-
-The @value{tramp} developers would like to circumvent this problem, so
-if you have an idea about it, please tell us. However, we are afraid
-it is not that simple: before saying @command{exec /bin/sh},
-@value{tramp} does not know which kind of shell it might be talking
-to. It could be a Bourne-ish shell like ksh or bash, or it could be a
-csh derivative like tcsh, or it could be zsh, or even rc. If the
-shell is Bourne-ish already, then it might be prudent to omit the
-@command{exec /bin/sh} step. But how to find out if the shell is
-Bourne-ish?
+When the remote host's @file{.profile} is also used for shells other
+than Bourne shell, then some incompatible syntaxes for commands in
+@file{.profile} may trigger errors in Bourne shell on the host and may
+not complete client's @value{tramp} connections.
+
+One example of a Bourne shell incompatible syntax in @file{.profile}:
+using @command{export FOO=bar} instead of @command{FOO=bar; export
+FOO}. After remote login, @value{tramp} will trigger an error during
+its execution of @command{/bin/sh} on the remote host because Bourne
+shell does not recognize the export command as entered in
+@file{.profile}.
+
+Likewise, (@code{~}) character in paths will cause errors because
+Bourne shell does not do (@code{~}) character expansions.
+
+One approach to avoiding these incompatibilities is to make all
+commands in @file{~/.shrc} and @file{~/.profile} Bourne shell
+compatible so @value{tramp} can complete connections to that remote.
+To accommodate using non-Bourne shells on that remote, use other
+shell-specific config files. For example, bash can use
+@file{~/.bash_profile} and ignore @file{.profile}.
@item Interactive shell prompt
-@value{tramp} redefines the shell prompt in order to parse the shell's
-output robustly. When calling an interactive shell by @kbd{M-x
-shell}, this doesn't look nice.
+@value{tramp} redefines the remote shell prompt internally for robust
+parsing. This redefinition affects the looks of a prompt in an
+interactive remote shell through commands, such as @kbd{M-x
+shell}. Such prompts, however, can be reset to something more readable
+and recognizable using these @value{tramp} variables.
-You can redefine the shell prompt by checking the environment variable
-@env{INSIDE_EMACS}, which is set by @value{tramp}, in your startup
-script @file{~/.emacs_SHELLNAME}. @env{SHELLNAME} might be the string
-@code{bash} or similar, in case of doubt you could set it the
-environment variable @env{ESHELL} in your @file{.emacs}:
+@value{tramp} sets the @env{INSIDE_EMACS} variable in the startup
+script file @file{~/.emacs_SHELLNAME}.
+
+@env{SHELLNAME} is @code{bash} or equivalent shell names. Change it by
+setting the environment variable @env{ESHELL} in the @file{.emacs} as
+follows:
@lisp
(setenv "ESHELL" "bash")
@end lisp
-Your file @file{~/.emacs_SHELLNAME} could contain code like
+Then re-set the prompt string in @file{~/.emacs_SHELLNAME} as follows:
@example
# Reset the prompt for remote Tramp shells.
@cindex Unix command nc
@cindex nc Unix command
-The @command{nc} command will be used with the @option{nc} method. On
-the remote host, a listener will be installed. Unfortunately, the
-command line syntax for this has been changed with the different
-@command{busybox} versions. @value{tramp} uses the following syntax
-(see @code{tramp-methods}):
+@value{tramp}'s @option{nc} method uses the @command{nc} command to
+install and execute a listener as follows (see @code{tramp-methods}):
@example
# nc -l -p 42
@end example
-If your remote @command{nc} refuses to accept the @command{-p}
-parameter, you could overwrite the syntax with the following form:
+The above command-line syntax has changed with @command{busybox}
+versions. If @command{nc} refuses the @command{-p} parameter, then
+overwrite as follows:
@lisp
(add-to-list
@end lisp
@noindent
-with @samp{192.168.0.1} being the IP address of your remote host
+where @samp{192.168.0.1} is the remote host IP address
(@pxref{Predefined connection information}).
@end table
@section Android shell setup hints
@cindex android shell setup
-Android devices use a restricted shell. They can be accessed via the
-@option{adb} method. However, this restricts the access to a USB
-connection, and it requires the installation of the Android SDK on the
-local host.
+@value{tramp} uses the @option{adb} method to access Android
+devices. Android devices provide a restricted shell access through an
+USB connection. The local host must have Andriod SDK installed.
-When an @command{sshd} process runs on the Android device, like
-provided by the @code{SSHDroid} app, any @option{ssh}-based method can
-be used. This requires some special settings.
+Applications such as @code{SSHDroid} that run @command{sshd} process
+on the Android device can accept any @option{ssh}-based methods
+provided these settings are adjusted:
-The default shell @code{/bin/sh} does not exist. Instead, you shall
-use just @code{sh}, which invokes the shell installed on the device.
-You can instruct @value{tramp} by this form:
+@code{sh} must be specified for remote shell since Android devices do
+not provide @code{/bin/sh}. @code{sh} will then invoke whatever shell is
+installed on the device with this setting:
@lisp
(add-to-list 'tramp-connection-properties
@end lisp
@noindent
-with @samp{192.168.0.26} being the IP address of your Android device
+where @samp{192.168.0.26} is the Android device's IP address.
(@pxref{Predefined connection information}).
-The user settings for the @env{PATH} environment variable must be
-preserved. It has also been reported, that the commands in
-@file{/system/xbin} are better suited than the ones in
-@file{/system/bin}. Add these setting:
+@value{tramp} requires preserving @env{PATH} environment variable from
+user settings. Android devices prefer @file{/system/xbin} path over
+@file{/system/bin}. Both of these are set as follows:
@lisp
(add-to-list 'tramp-remote-path 'tramp-own-remote-path)
@end lisp
@noindent
-If the Android device is not @samp{rooted}, you must give the shell a
-writable directory for temporary files:
+When the Android device is not @samp{rooted}, specify a writable
+directory for temporary files:
@lisp
(add-to-list 'tramp-remote-process-environment "TMPDIR=$HOME")
@end lisp
@noindent
-Now you shall be able to open a remote connection with @kbd{C-x C-f
-@trampfn{ssh, , 192.168.0.26#2222, }}, given that @command{sshd}
-listens on port @samp{2222}.
+Open a remote connection with the command @kbd{C-x C-f @trampfn{ssh, ,
+192.168.0.26#2222, }}, where @command{sshd} is listening on port
+@samp{2222}.
-It is also recommended to add a corresponding entry to your
-@file{~/.ssh/config} for that connection, like
+To add a corresponding entry to the @file{~/.ssh/config} file
+(recommended), use this:
@example
Host android
@end example
@noindent
-In this case, you must change the setting for the remote shell to
+To use the host name @samp{android} instead of the IP address shown in
+the previous example, fix the connection properties as follows:
@lisp
(add-to-list 'tramp-connection-properties
@end lisp
@noindent
-You would open the connection with @kbd{C-x C-f @trampfn{ssh, ,
-android, }} then.
+Open a remote connection with a more concise command @kbd{C-x C-f
+@trampfn{ssh, , android, }}.
@node Auto-save and Backup
@vindex bkup-backup-directory-info
@end ifset
-Normally, @value{emacsname} writes backup files to the same directory
-as the original files, but this behavior can be changed via the
-variable
+To avoid @value{tramp} from saving backup files owned by root to
+locations accessible to others, default backup settings in
@ifset emacs
-@code{backup-directory-alist}.
+@code{backup-directory-alist}
@end ifset
@ifset xemacs
-@code{bkup-backup-directory-info}.
+@code{bkup-backup-directory-info}
@end ifset
-In connection with @value{tramp}, this can have unexpected side
-effects. Suppose that you specify that all backups should go to the
-directory @file{~/.emacs.d/backups/}, and then you edit the file
-@file{@trampfn{su, root, localhost, /etc/secretfile}}. The effect is
-that the backup file will be owned by you and not by root, thus
-possibly enabling others to see it even if they were not intended to
-see it.
+have to be altered.
+
+Here's a scenario where files could be inadvertently
+exposed. @value{emacsname} by default writes backup files to the same
+directory as the original files unless changed to another location,
+such as @file{~/.emacs.d/backups/}. Such a directory will also be used
+by default by @value{tramp} when using, say, a restricted file
+@file{@trampfn{su, root, localhost, /etc/secretfile}}. The backup file
+of the secretfile is now owned by the user logged in from tramp and
+not root.
When
@ifset emacs
@end ifset
is @code{nil} (the default), such problems do not occur.
-Therefore, it is useful to set special values for @value{tramp}
-files. For example, the following statement effectively ``turns off''
-the effect of
-@ifset emacs
-@code{backup-directory-alist}
-@end ifset
-@ifset xemacs
-@code{bkup-backup-directory-info}
-@end ifset
-for @value{tramp} files:
+To ``turns off'' the backup feature for @value{tramp} files and stop
+@value{tramp} from saving to the backup directory, use this:
@ifset emacs
@lisp
@end ifset
@ifset emacs
-It is also possible to disable backups depending on the used method.
-The following code disables backups for the @option{su} and
+@noindent
+Disabling backups can be targetted to just @option{su} and
@option{sudo} methods:
@lisp
@end lisp
@end ifset
-
-Another possibility is to use the @value{tramp} variable
+Another option is to create better backup file naming with user and
+host names prefixed to the file name. For example, transforming
+@file{/etc/secretfile} to
+@file{~/.emacs.d/backups/!su:root@@localhost:!etc!secretfile}, set the
+@value{tramp} variable
@ifset emacs
-@code{tramp-backup-directory-alist}.
+@code{tramp-backup-directory-alist}
@end ifset
@ifset xemacs
-@code{tramp-bkup-backup-directory-info}.
+@code{tramp-bkup-backup-directory-info}
@end ifset
-This variable has the same meaning like
+from the existing variable
@ifset emacs
@code{backup-directory-alist}.
@end ifset
@ifset xemacs
@code{bkup-backup-directory-info}.
@end ifset
-If a @value{tramp} file is backed up, and DIRECTORY is an absolute
-local file name, DIRECTORY is prepended with the @value{tramp} file
-name prefix of the file to be backed up.
+
+Then @value{tramp} backs up to a file name that is transformed with a
+prefix consisting of the DIRECTORY name. This file name prefixing
+happens only when the DIRECTORY is an absolute local file name.
@noindent
Example:
~/.emacs.d/backups/![su!root@@localhost]!etc!secretfile~}}
@end ifset
-The same problem can happen with auto-saving files.
+Just as for backup files, similar issues of file naming affect
+auto-saving @value{tramp} files.
@ifset emacs
-The variable @code{auto-save-file-name-transforms} keeps information,
-on which directory an auto-saved file should go. By default, it is
-initialized for @value{tramp} files to the local temporary directory.
-
-On some versions of @value{emacsname}, namely the version built for
-Debian GNU/Linux, the variable @code{auto-save-file-name-transforms}
-contains the directory where @value{emacsname} was built. A
-workaround is to manually set the variable to a sane value.
+Auto-saved files are saved in the directory specified by the variable
+@code{auto-save-file-name-transforms}. By default this is set to the
+local temporary directory. But in some versions of Debian GNU/Linux,
+this points to the source directory where the @value{emacsname} was
+compiled. Reset such values to a valid directory.
-If auto-saved files should go into the same directory as the original
-files, @code{auto-save-file-name-transforms} should be set to @code{nil}.
+Set @code{auto-save-file-name-transforms} to @code{nil} to save
+auto-saved files to the same directory as the original file.
-Another possibility is to set the variable
-@code{tramp-auto-save-directory} to a proper value.
+Alternatively, set the variable @code{tramp-auto-save-directory} to
+direct all auto saves to that location.
@end ifset
@ifset xemacs
-For this purpose you can set the variable @code{auto-save-directory}
-to a proper value.
+@code{auto-save-directory} can also be used here instead of other
+locations specfied above.
@end ifset
-
@node Windows setup hints
@section Issues with Cygwin ssh
@cindex Cygwin, issues
-This section needs a lot of work! Please help.
+This section is incomplete. Please share your solutions.
@cindex method sshx with Cygwin
@cindex sshx method with Cygwin
-The recent Cygwin installation of @command{ssh} works only with a
-Cygwinized @value{emacsname}. You can check it by typing @kbd{M-x
-eshell}, and starting @kbd{ssh test.host}. The problem is evident
-if you see a message like this:
+
+Cygwin's @command{ssh} works only with a Cygwin version of
+@value{emacsname}. To check for compatibility: type @kbd{M-x eshell}, and
+start @kbd{ssh test.host}. Incompatbilities trigger this message:
@example
Pseudo-terminal will not be allocated because stdin is not a terminal.
@end example
-Older @command{ssh} versions of Cygwin are told to cooperate with
-@value{tramp} selecting @option{sshx} as the connection method. You
-can find information about setting up Cygwin in their FAQ at
-@uref{http://cygwin.com/faq/}.
+Some older versions of Cygwin's @command{ssh} work with the
+@option{sshx} access method. Consult Cygwin's FAQ at
+@uref{http://cygwin.com/faq/} for details.
+
@cindex method scpx with Cygwin
@cindex scpx method with Cygwin
-If you wish to use the @option{scpx} connection method, then you might
-have the problem that @value{emacsname} calls @command{scp} with a
-Windows file name such as @code{c:/foo}. The Cygwin version of
-@command{scp} does not know about Windows file names and interprets
-this as a remote file name on the host @code{c}.
-One possible workaround is to write a wrapper script for @option{scp}
-which converts the Windows file name to a Cygwinized file name.
+When using the @option{scpx} access method, @value{emacsname} may call
+@command{scp} with Windows file naming, such as @code{c:/foo}. But
+the version of @command{scp} that is installed with Cygwin does not
+know about Windows file naming, which causes it to incorrectly look
+for a host named @code{c}.
+
+A workaround: write a wrapper script for @option{scp} to convert
+Windows file names to Cygwin file names.
@cindex Cygwin and ssh-agent
@cindex SSH_AUTH_SOCK and @value{emacsname} on Windows
-If you want to use either @option{ssh} based method on Windows, then
-you might encounter problems with @command{ssh-agent}. Using this
-program, you can avoid typing the pass-phrase every time you log in.
-However, if you start @value{emacsname} from a desktop shortcut, then
-the environment variable @env{SSH_AUTH_SOCK} is not set and so
-@value{emacsname} and thus @value{tramp} and thus @command{ssh} and
-@command{scp} started from @value{tramp} cannot communicate with
-@command{ssh-agent}. It works better to start @value{emacsname} from
-the shell.
-If anyone knows how to start @command{ssh-agent} under Windows in such a
-way that desktop shortcuts can profit, please holler. I don't really
-know anything at all about Windows@dots{}
+When using the @command{ssh-agent} on Windows for password-less
+interaction, @option{ssh} methods depend on the environment variable
+@env{SSH_AUTH_SOCK}. But this variable is not set when
+@value{emacsname} is started from a Desktop shortcut and
+authentication fails.
+
+One workaround is to use a Windows based SSH Agent, such as
+Pageant. It is part of the Putty Suite of tools.
+
+The fallback is to start @value{emacsname} from a shell.
@node Usage
@chapter Using @value{tramp}
@cindex using @value{tramp}
-Once you have installed @value{tramp} it will operate fairly
-transparently. You will be able to access files on any remote host
-that you can log in to as though they were local.
-
-Files are specified to @value{tramp} using a formalized syntax specifying the
-details of the system to connect to. This is similar to the syntax used
-by the @value{ftppackagename} package.
+@value{tramp} operates transparently, accessing remote files as if
+they are local. However, @value{tramp} employs a formalized remote
+file naming syntax to perform its functions transparently. This
+syntax consists of many parts specifying access methods,
+authentication, host names, and file names.
+@ifset emacs
+@value{ftppackagename} uses a similar syntax.
+@end ifset
@cindex type-ahead
-Something that might happen which surprises you is that
-@value{emacsname} remembers all your keystrokes, so if you see a
-password prompt from @value{emacsname}, say, and hit @kbd{@key{RET}}
-twice instead of once, then the second keystroke will be processed by
-@value{emacsname} after @value{tramp} has done its thing. Why, this
-type-ahead is normal behavior, you say. Right you are, but be aware
-that opening a remote file might take quite a while, maybe half a
-minute when a connection needs to be opened. Maybe after half a
-minute you have already forgotten that you hit that key!
+
+Unlike opening local files in @value{emacsname}, which are
+instantaneous, opening remote files in @value{tramp} is slower at
+first. Sometimes there is a noticable delay before the prompts for
+passwords or authentication appear in the minibuffer. Hitting
+@kbd{@key{RET}} or other keys during this gap will be processed by
+@value{emacsname}. This type-ahead facility is a feature of
+@value{emacsname} that may cause missed prompts when using
+@value{tramp}.
@menu
* File name Syntax:: @value{tramp} file name conventions.
@cindex file name syntax
@cindex file name examples
-To access the file @var{localname} on the remote host @var{host}
-you would specify the file name @file{@trampfn{, , host,
-localname}}. This will connect to @var{host} and transfer the file
-using the default method. @xref{Default Method}.
-
-Some examples of @value{tramp} file names are shown below.
+@file{@trampfn{, , host, localfilename}}
+opens file @var{localfilename} on the remote host @var{host}, using
+the default method. @xref{Default Method}.
@table @file
@item @value{prefix}melancholia@value{postfix}.emacs
-Edit the file @file{.emacs} in your home directory on the host
+For the file @file{.emacs} located in the home directory, on the host
@code{melancholia}.
@item @value{prefix}melancholia.danann.net@value{postfix}.emacs
-This edits the same file, using the fully qualified domain name of
+For the file @file{.emacs} specified using the fully qualified domain name of
the host.
@item @value{prefix}melancholia@value{postfix}~/.emacs
-This also edits the same file; the @file{~} is expanded to your
-home directory on the remote host, just like it is locally.
+For the file @file{.emacs} specified using the @file{~}, which is expanded.
@item @value{prefix}melancholia@value{postfix}~daniel/.emacs
-This edits the file @file{.emacs} in the home directory of the user
-@code{daniel} on the host @code{melancholia}. The @file{~<user>}
-construct is expanded to the home directory of that user on the remote
-host.
+For the file @file{.emacs} located in @code{daniel}'s home directory
+on the host, @code{melancholia}. The @file{~<user>} construct is
+expanded to the home directory of that user on the remote host.
@item @value{prefix}melancholia@value{postfix}/etc/squid.conf
-This edits the file @file{/etc/squid.conf} on the host
-@code{melancholia}.
+For the file @file{/etc/squid.conf} on the host @code{melancholia}.
@end table
-@var{host} can also be an IPv4 or IPv6 address, like in
-@file{@trampfn{, , 127.0.0.1, .emacs}} or @file{@trampfn{, ,
+@var{host} can take IPv4 or IPv6 address, as in @file{@trampfn{, ,
+127.0.0.1, .emacs}} or @file{@trampfn{, ,
@value{ipv6prefix}::1@value{ipv6postfix}, .emacs}}.
@ifset emacs
For syntactical reasons, IPv6 addresses must be embedded in square
brackets @file{@value{ipv6prefix}} and @file{@value{ipv6postfix}}.
@end ifset
-Unless you specify a different name to use, @value{tramp} will use the
-current local user name as the remote user name to log in with. If you
-need to log in as a different user, you can specify the user name as
-part of the file name.
+By default, @value{tramp} will use the current local user name as the
+remote user name for log in to the remote host. Specifying a different
+name using the proper syntax will override this default behavior:
+
+@example
+@trampfn{, user, host, path/to.file}
+@end example
+
+@file{@trampfn{, daniel, melancholia, .emacs}} is for file
+@file{.emacs} in @code{daniel}'s home directory on the host,
+@code{melancholia}.
-To log in to the remote host as a specific user, you use the syntax
-@file{@trampfn{, user, host, path/to.file}}. That means that
-connecting to @code{melancholia} as @code{daniel} and editing
-@file{.emacs} in your home directory you would specify
-@file{@trampfn{, daniel, melancholia, .emacs}}.
+Specify other file access methods (@pxref{Inline methods},
+@pxref{External methods}) as part of the file name.
-It is also possible to specify other file transfer methods
-(@pxref{Inline methods}, @pxref{External methods}) as part of the
-file name.
@ifset emacs
-This is done by putting the method before the user and host name, as
-in @file{@value{prefix}@var{method}@value{postfixhop}} (Note the
-trailing colon).
+Method name comes before user name, as in
+@file{@value{prefix}@var{method}@value{postfixhop}} (Note the trailing
+colon).
@end ifset
@ifset xemacs
This is done by replacing the initial @file{@value{prefix}} with
-@file{@value{prefix}<method>@value{postfixhop}}. (Note the trailing
+@file{@value{prefix}@var{method}@value{postfixhop}} (Note the trailing
slash!).
@end ifset
-The user, host and file specification remain the same.
+The syntax specificaton for user, host, and file do not change.
-So, to connect to the host @code{melancholia} as @code{daniel},
-using the @option{ssh} method to transfer files, and edit
-@file{.emacs} in my home directory I would specify the file name
-@file{@trampfn{ssh, daniel, melancholia, .emacs}}.
+To connect to the host @code{melancholia} as @code{daniel}, using
+@option{ssh} method for @file{.emacs} in @code{daniel}'s home
+directory, the full specification is: @file{@trampfn{ssh, daniel,
+melancholia, .emacs}}.
-@ifset emacs
-A remote file name containing a host name only, which is equal to a
-method name, is not allowed. If such a host name is used, it must
-always be preceded by an explicit method name, like
-@file{@value{prefix}ssh@value{postfixhop}ssh@value{postfix}}.
-@end ifset
+A remote file name containing a host name, which is the same string as
+a method name, is not allowed.
-Finally, for some methods it is possible to specify a different port
-number than the default one, given by the method. This is specified
-by adding @file{#<port>} to the host name, like in @file{@trampfn{ssh,
-daniel, melancholia#42, .emacs}}.
+For specifying port numbers, affix @file{#<port>} to the host
+name. For example: @file{@trampfn{ssh, daniel, melancholia#42,
+.emacs}}.
@node File name completion
@section File name completion
@cindex file name completion
-File name completion works with @value{tramp} for completion of method
-names, of user names and of host names as well as for completion of
-file names on remote hosts.
+@value{tramp} can complete the following @value{tramp} file name
+components: method names, user names, host names, and file names
+located on remote hosts.
@ifset emacs
-In order to enable this, partial completion must be activated in your
-@file{.emacs}.
+Enable this by activating partial completion in @file{.emacs}.
@ifinfo
@xref{Completion Options, , , @value{emacsdir}}.
@end ifinfo
@end ifset
-If you, for example, type @kbd{C-x C-f @value{prefix}t
-@key{TAB}}, @value{tramp} might give you as result the choice for
+For example, type @kbd{C-x C-f @value{prefix}t @key{TAB}},
+@value{tramp} completion choices show up as
@example
@c @multitable {@trampfn{telnet, , melancholia.danann.net,}} {@trampfn{telnet, , 192.168.0.1,}}
@end ifset
and @samp{@value{prefixhop}toto@value{postfix}}
might be a host @value{tramp} has detected in your @file{~/.ssh/known_hosts}
-file (given you're using default method @option{ssh}).
+file (when using @option{ssh} as default method).
-If you go on to type @kbd{e @key{TAB}}, the minibuffer is completed to
-@samp{@value{prefix}telnet@value{postfixhop}}.
-Next @kbd{@key{TAB}} brings you all host names @value{tramp} detects in
-your @file{/etc/hosts} file, let's say
+Type @kbd{e @key{TAB}} for the minibuffer completion to
+@samp{@value{prefix}telnet@value{postfixhop}}. Typing @kbd{@key{TAB}}
+shows host names @value{tramp} from @file{/etc/hosts} file, for example.
@example
@multitable @columnfractions .5 .5
@end multitable
@end example
-Now you can choose the desired host, and you can continue to
-complete file names on that host.
+Choose a host from the above list and then continue to complete file
+names on that host.
-If the configuration files (@pxref{Customizing Completion}), which
-@value{tramp} uses for analysis of completion, offer user names, those user
-names will be taken into account as well.
+When the configuration (@pxref{Customizing Completion}) includes user
+names, then the completion lists will account for the user names as well.
-Remote hosts which have been visited in the past and kept
-persistently (@pxref{Connection caching}) will be offered too.
+Remote hosts previously visited or hosts whose connections are kept
+persistently (@pxref{Connection caching}) will be included in the
+completion lists.
-Once the remote host identification is completed, it comes to
-file name completion on the remote host. This works pretty much like
-for files on the local host, with the exception that minibuffer
-killing via a double-slash works only on the file name part, except
-that file name part starts with @file{//}.
+After remote host name completion comes completion of file names on
+the remote host. It works the same as on loal host file completion
+except when killing with double-slash @file{//} kills only the file
+name part of the @value{tramp} file name syntax.
@ifset emacs
A triple-slash stands for the default behavior.
@end ifset
@end ifset
@end example
-A remote directory might have changed its contents out of
-@value{emacsname} control, for example by creation or deletion of
-files by other processes. Therefore, during file name completion, the
-remote directory contents are reread regularly in order to detect such
-changes, which would be invisible otherwise (@pxref{Connection caching}).
+During file name completion, remote directory contents are re-read
+regularly to account for any changes in the filesystem that may affect
+the completion candidates. Such re-reads can account for changes to
+the file system by applications outside @value{emacsname}
+(@pxref{Connection caching}).
-@vindex tramp-completion-reread-directory-timeout
@defopt tramp-completion-reread-directory-timeout
-This custom option defines the number of seconds since last remote
-command before rereading a directory contents. A value of 0 would
-require an immediate reread during file name completion, @code{nil}
-means to use always cached values for the directory contents.
+@vindex tramp-completion-reread-directory-timeout
+The timeout is number of seconds since last remote command for
+rereading remote directory contents. 0 re-reads immediately during
+file name completion, @code{nil} uses cached directory contents.
@end defopt
@cindex multi-hop, ad-hoc
@cindex proxy hosts, ad-hoc
-Multiple hops are configured with the variable
-@code{tramp-default-proxies-alist} (@pxref{Multi-hops}). However,
-sometimes it is desirable to reach a remote host immediately, without
-configuration changes. This can be reached by an ad-hoc specification
-of the proxies.
+@value{tramp} file name syntax can accommodate ad hoc specification of
+multiple proxies without using @code{tramp-default-proxies-alist}
+configuration setup(@pxref{Multi-hops}).
-A proxy looks like a remote file name specification without the local
-file name part. It is prepended to the target remote file name,
-separated by @samp{|}. As an example, a remote file on
-@samp{you@@remotehost}, passing the proxy @samp{bird@@bastion}, could
-be opened by
+Each proxy is specified using the same syntax as the remote host
+specification minus the file name part. Each hop is separated by a
+@samp{|}. Chain the proxies from the starting host to the destination
+remote host name and file name. For example, hopping over a single
+proxy @samp{bird@@bastion} to a remote file on @samp{you@@remotehost}:
@example
@c @kbd{C-x C-f @trampfn{ssh@value{postfixhop}bird@@bastion|ssh, you,
@kbd{C-x C-f @value{prefix}ssh@value{postfixhop}bird@@bastion|ssh@value{postfixhop}you@@remotehost@value{postfix}/path}
@end example
-Multiple hops can be cascaded, separating all proxies by @samp{|}.
-The proxies can also contain the patterns @code{%h} or @code{%u}.
+Proxies can take patterns @code{%h} or @code{%u}.
-The ad-hoc definition is added on the fly to
-@code{tramp-default-proxies-alist}. Therefore, during the lifetime of
-the @value{emacsname} session it is not necessary to enter this ad-hoc
-specification, again. The remote file name @samp{@trampfn{ssh, you,
-remotehost, /path}} would be sufficient from now on.
+@value{tramp} adds the ad-hoc definitions on the fly to
+@code{tramp-default-proxies-alist} and is available for re-use during
+that @value{emacsname} session. Subsequent @value{tramp} connections
+to the same remote host can then use the shortcut form:
+@samp{@trampfn{ssh, you, remotehost, /path}}.
-@vindex tramp-save-ad-hoc-proxies
@defopt tramp-save-ad-hoc-proxies
-This custom option controls whether ad-hoc definitions are kept
-persistently in @option{tramp-default-proxies-alist}. That means,
-those definitions are available also for future @value{emacsname}
-sessions.
+@vindex tramp-save-ad-hoc-proxies
+For ad-hoc definitions to be saved automatically in
+@option{tramp-default-proxies-alist} for future @value{emacsname}
+sessions, set @option{tramp-save-ad-hoc-proxies}.
+
+@lisp
+(setq tramp-save-ad-hoc-proxies t)
+@end lisp
@end defopt
@cindex compile
@cindex recompile
-@value{tramp} supports running processes on a remote host. This
-allows to exploit @value{emacsname} packages without modification for
-remote file names. It does not work for the @option{ftp} method.
-Association of a pty, as specified in @code{start-file-process}, is
-not supported.
+@value{tramp} supports starting new running processes on the remote
+host for discovering remote file names. @value{emacsname} packages on
+the remote host need no specific modifications for @value{tramp}'s
+use.
+
+This type of integration does not work with the @option{ftp} method,
+and does not support the pty association as specified in
+@code{start-file-process}.
@code{process-file} and @code{start-file-process} work on the remote
host when the variable @code{default-directory} is remote:
"/bin/sh" "-c" "grep -e tramp *"))
@end lisp
+
@ifset emacsgvfs
-If the remote host is mounted via GVFS (see @ref{GVFS based methods}),
-the remote filesystem is mounted locally. Therefore, there are no
-remote processes; all processes run still locally on your host with
-an adapted @code{default-directory}. This section does not apply for
-such connection methods.
+Remote processes do not apply to GVFS (see @ref{GVFS based methods})
+because the remote file system is mounted on the local host and
+@value{tramp} just accesses by changing the @code{default-directory}.
@end ifset
-Remote processes are started when a corresponding command is executed
-from a buffer belonging to a remote file or directory. Up to now, the
-packages @file{compile.el} (commands like @code{compile} and
-@code{grep}) and @file{gud.el} (@code{gdb} or @code{perldb}) have been
-integrated. Integration of further packages is planned, any help for
-this is welcome!
+@value{tramp} starts a remote process when a command is executed in a
+remote file or directory buffer. As of now, these packages have been
+integrated to work with @value{tramp}: @file{compile.el} (commands
+like @code{compile} and @code{grep}) and @file{gud.el} (@code{gdb} or
+@code{perldb}).
-When your program is not found in the default search path
-@value{tramp} sets on the remote host, you should either use an
-absolute path, or extend @code{tramp-remote-path} (see @ref{Remote
-programs}):
+For @value{tramp} to find the command on the remote, it must be
+accessible through the default search path as setup by @value{tramp}
+upon first connection. Alternatively, use an absolute path or extend
+@code{tramp-remote-path} (see @ref{Remote programs}):
@lisp
(add-to-list 'tramp-remote-path "~/bin")
(add-to-list 'tramp-remote-path "/appli/pub/bin")
@end lisp
-The environment for your program can be adapted by customizing
-@code{tramp-remote-process-environment}. This variable is a list of
-strings. It is structured like @code{process-environment}. Each
-element is a string of the form @samp{ENVVARNAME=VALUE}. An entry
-@samp{ENVVARNAME=} disables the corresponding environment variable,
-which might have been set in your init file like @file{~/.profile}.
+Customize @code{tramp-remote-process-environment} to suit the remote
+program's environment for the remote host.
+@code{tramp-remote-process-environment} is a list of strings
+structured similar to @code{process-environment}, where each element
+is a string of the form @samp{ENVVARNAME=VALUE}.
+
+To avoid any conflicts with local host variables set through local
+configuration files, such as @file{~/.profile}, use @samp{ENVVARNAME=}
+to unset them for the remote environment.
@noindent
-Adding an entry can be performed via @code{add-to-list}:
+Use @code{add-to-list} to add entries:
@lisp
(add-to-list 'tramp-remote-process-environment "JAVA_HOME=/opt/java")
@end lisp
-Changing or removing an existing entry is not encouraged. The default
-values are chosen for proper @value{tramp} work. Nevertheless, if for
-example a paranoid system administrator disallows changing the
-@env{HISTORY} environment variable, you can customize
-@code{tramp-remote-process-environment}, or you can apply the
-following code in your @file{.emacs}:
+Modifying or deleting already existing values in the
+@code{tramp-remote-process-environment} list may not be feasible on
+restricted remote hosts. For example, some system administrators
+disallow changing @env{HISTORY} variable. To accommodate such
+restrictions when using @value{tramp}, fix the
+@code{tramp-remote-process-environment} by the following code in the
+local @file{.emacs} file:
@lisp
(let ((process-environment tramp-remote-process-environment))
(setq tramp-remote-process-environment process-environment))
@end lisp
-When running @code{process-file} or @code{start-file-process} on a
-remote @code{default-directory}, the default settings in
-@code{process-environment} are not used as it is the case for local
-processes. However, if you need environment variables other than set
-in @code{tramp-remote-process-environment}, you can let-bind them to
-@code{process-environment}. Only those variables will be set then:
+@value{tramp} does not use the defaults specified in
+@code{process-environment} for running @code{process-file} or
+@code{start-file-process} on remote hosts. When values from
+@code{process-environment} are needed for remote processes, then set
+them as follows:
@lisp
(let ((process-environment (cons "HGPLAIN=1" process-environment)))
(process-file @dots{}))
@end lisp
-This works only for environment variables which are not set already in
+This works only for environment variables not already set in the
@code{process-environment}.
-If you use other @value{emacsname} packages which do not run
-out-of-the-box on a remote host, please let us know. We will try to
-integrate them as well. @xref{Bug Reports}.
+For integrating other @value{emacsname} packages so @value{tramp} can
+execute remotely, please file a bug report. @xref{Bug Reports}.
@subsection Running remote programs that create local X11 windows
-If you want to run a remote program, which shall connect the X11
-server you are using with your local host, you can set the
-@env{DISPLAY} environment variable on the remote host:
+To allow a remote program to create an X11 window on the local host,
+set the @env{DISPLAY} environment variable for the remote host as
+follows in the local @file{.emacs} file:
@lisp
(add-to-list 'tramp-remote-process-environment
@end lisp
@noindent
-@code{(getenv "DISPLAY")} shall return a string containing a host
-name, which can be interpreted on the remote host; otherwise you might
-use a fixed host name. Strings like @code{:0} cannot be used properly
-on the remote host.
-
-Another trick might be that you put @code{ForwardX11 yes} or
-@code{ForwardX11Trusted yes} to your @file{~/.ssh/config} file for
-that host.
+@code{(getenv "DISPLAY")} should return a recognizable name for the
+local host that the remote host can redirect X11 window
+interactions. If querying for a recognizable name is not possible for
+whatever reason, then replace @code{(getenv "DISPLAY")} with a
+hard-coded, fixed name. Note that using @code{:0} for X11 display name
+here will not work as expected.
+
+An alternate approach is specify @code{ForwardX11 yes} or
+@code{ForwardX11Trusted yes} in the file @file{~/.ssh/config} on the
+local host.
@subsection Running @code{shell} on a remote host
@cindex shell
-Calling @kbd{M-x shell} in a buffer related to a remote host runs the
-local shell as defined in @option{shell-file-name}. This might be
-also a valid file name for a shell to be applied on the remote host,
-but it will fail at least when your local and remote hosts belong to
-different system types, like @samp{windows-nt} and @samp{gnu/linux}.
-
-You must set the variable @option{explicit-shell-file-name} to the
-shell file name on the remote host, in order to start that shell on
-the remote host.
+Set @option{explicit-shell-file-name} to the appropriate shell name
+when using @value{tramp} between two hosts with different operating
+systems, such as @samp{windows-nt} and @samp{gnu/linux}. This option
+ensures the correct name of the remote shell program.
@ifset emacs
-Starting with Emacs 24 this won't be necessary, if you call
-@code{shell} interactively. You will be asked for the remote shell
-file name, if you are on a remote buffer, and if
-@option{explicit-shell-file-name} is equal to @code{nil}.
+Starting with Emacs 24, when @option{explicit-shell-file-name} is
+equal to @code{nil}, calling @code{shell} interactively will prompt
+for a shell name.
@end ifset
@subsection Running @code{shell-command} on a remote host
@cindex shell-command
-@code{shell-command} allows to execute commands in a shell, either
-synchronously, either asynchronously. This works also on remote
-hosts. Example:
+@code{shell-command} executes commands synchronously or asynchronously
+on remote hosts and displays output in buffers on the local
+host. Example:
@example
@kbd{C-x C-f @trampfn{sudo, , , } @key{RET}}
@kbd{M-! tail -f /var/log/syslog.log & @key{RET}}
@end example
-You will see the buffer @file{*Async Shell Command*}, containing the
-continuous output of the @command{tail} command.
+@command{tail} command outputs continuously to the local buffer,
+@file{*Async Shell Command*}
@ifset emacs
-A similar behavior can be reached by @kbd{M-x auto-revert-tail-mode},
-if available.
+@kbd{M-x auto-revert-tail-mode} runs similarly showing continuous output.
@end ifset
@subsection Running @code{eshell} on a remote host
@cindex eshell
-@value{tramp} is integrated into @file{eshell.el}. That is, you can
-open an interactive shell on your remote host, and run commands there.
-After you have started @kbd{M-x eshell}, you could perform commands
-like this:
+@value{tramp} is integrated into @file{eshell.el}, which enables
+interactive eshell sessions on remote hosts at the command prompt.
+You must add the module @code{eshell-tramp} to
+@code{eshell-modules-list}. Here's a sample interaction after opening
+@kbd{M-x eshell} on a remote host:
@example
@b{~ $} cd @trampfn{sudo, , , /etc} @key{RET}
@end example
@ifset emacs
-Since @value{emacsname} 23.2, @code{eshell} has also an own
-implementation of the @code{su} and @code{sudo} commands. Both
-commands change the default directory of the @file{*eshell*} buffer to
-the value related to the user the command has switched to. This works
-even on remote hosts, adding silently a corresponding entry to the
-variable @code{tramp-default-proxies-alist} (@pxref{Multi-hops}):
+@code{eshell} in @value{emacsname} 23.2 added custom @code{su} and
+@code{sudo} commands that set the default directory correctly for the
+@file{*eshell*} buffer. @value{tramp} silently updates
+@code{tramp-default-proxies-alist} with an entry for this directory
+(@pxref{Multi-hops}):
@example
@b{~ $} cd @trampfn{ssh, user, remotehost, /etc} @key{RET}
@cindex gdb
@cindex perldb
-@file{gud.el} offers a unified interface to several symbolic
-debuggers
+@file{gud.el} provides a unified interface to symbolic debuggers
@ifset emacs
@ifinfo
(@ref{Debuggers, , , @value{emacsdir}}).
@end ifinfo
@end ifset
-With @value{tramp}, it is possible to debug programs on
-remote hosts. You can call @code{gdb} with a remote file name:
+@value{tramp} can run debug on remote hosts by calling @code{gdb}
+with a remote file name:
@example
@kbd{M-x gdb @key{RET}}
@b{Run gdb (like this):} gdb --annotate=3 @trampfn{ssh, , host, ~/myprog} @key{RET}
@end example
-The file name can also be relative to a remote default directory.
-Given you are in a buffer that belongs to the remote directory
-@trampfn{ssh, , host, /home/user}, you could call
+Relative file names are based on the remote default directory. When
+@file{myprog.pl} exists in @file{@trampfn{ssh, , host, /home/user}},
+valid calls include:
@example
@kbd{M-x perldb @key{RET}}
@b{Run perldb (like this):} perl -d myprog.pl @key{RET}
@end example
-It is not possible to use just the absolute local part of a remote
-file name as program to debug, like @kbd{perl -d
-/home/user/myprog.pl}, though.
+Just the local part of a remote file name, such as @kbd{perl -d
+/home/user/myprog.pl}, is not possible.
-Arguments of the program to be debugged are taken literally. That
-means, file names as arguments must be given as ordinary relative or
-absolute file names, without any remote specification.
+Arguments of the program to be debugged must be literal, can take
+relative or absolute paths, but not remote paths.
@subsection Running remote processes on Windows hosts
@cindex winexe
@cindex powershell
-With the help of the @command{winexe} it is possible tu run processes
-on a remote Windows host. @value{tramp} has implemented this for
-@code{process-file} and @code{start-file-process}.
+@command{winexe} runs processes on a remote Windows host, and
+@value{tramp} can use it for @code{process-file} and
+@code{start-file-process}.
-The variable @code{tramp-smb-winexe-program} must contain the file
-name of your local @command{winexe} command. On the remote host,
-Powershell V2.0 must be installed; it is used to run the remote
-process.
+@code{tramp-smb-winexe-program} specifies the local @command{winexe}
+command. Powershell V2.0 on the remote host is required to run
+processes triggered from @value{tramp}.
-In order to open a remote shell on the Windows host via @kbd{M-x
-shell}, you must set the variables @option{explicit-shell-file-name}
-and @option{explicit-*-args}. If you want, for example, run
-@command{cmd}, you must set:
+@option{explicit-shell-file-name} and @option{explicit-*-args} have to
+be set properly so @kbd{M-x shell} can open a proper remote shell on a
+Windows host. To open @command{cmd}, set it as follows:
@lisp
(setq explicit-shell-file-name "cmd"
@end lisp
@noindent
-In case of running @command{powershell} as remote shell, the settings are
+To open @command{powershell} as a remote shell, use this:
@lisp
(setq explicit-shell-file-name "powershell"
@section Cleanup remote connections
@cindex cleanup
-Sometimes it is useful to cleanup remote connections. The following
-commands support this.
+@value{tramp} provides several ways to flush remote connections.
@deffn Command tramp-cleanup-connection vec
This command flushes all connection related objects. @option{vec} is
-the internal representation of a remote connection. Called
-interactively, the command offers all active remote connections in the
-minibuffer as remote file name prefix like @file{@trampfn{method,
-user, host, }}. The cleanup includes password cache (@pxref{Password
-handling}), file cache, connection cache (@pxref{Connection caching}),
-connection buffers.
+the internal representation of a remote connection. When called
+interactively, this command lists active remote connections in the
+minibuffer. Each connection is of the format @file{@trampfn{method,
+user, host, }}. Flushing remote connections also cleans the password
+cache (@pxref{Password handling}), file cache, connection cache
+(@pxref{Connection caching}), and connection buffers.
@end deffn
@deffn Command tramp-cleanup-this-connection
-This command flushes all objects of the current buffer's remote
-connection. The same objects are removed as in
-@code{tramp-cleanup-connection}.
+Flushes only the current buffer's remote connection objects, the same
+as in @code{tramp-cleanup-connection}.
@end deffn
@deffn Command tramp-cleanup-all-connections
-This command flushes objects for all active remote connections. The
-same objects are removed as in @code{tramp-cleanup-connection}.
+Flushes all active remote connection objects, the same as in
+@code{tramp-cleanup-connection}.
@end deffn
@deffn Command tramp-cleanup-all-buffers
-Like in @code{tramp-cleanup-all-connections}, all remote connections
-are cleaned up. Additionally all buffers, which are related to a
-remote connection, are killed.
+Just as for @code{tramp-cleanup-all-connections}, all remote
+connections are cleaned up in addition to killing buffers related to
+that remote connection.
@end deffn
@chapter Reporting Bugs and Problems
@cindex bug reports
-Bugs and problems with @value{tramp} are actively worked on by the
-development team. Feature requests and suggestions are also more than
-welcome.
+@value{tramp}'s development team is actively engaged in solving bugs
+and problems and looks to feature requests and suggestions.
+
+@value{tramp}'s mailing list is the place for more advice and
+information on working with @value{tramp}, solving problems,
+discussing, and general discussions about @value{tramp}.
-The @value{tramp} mailing list is a great place to get information on
-working with @value{tramp}, solving problems and general discussion
-and advice on topics relating to the package. It is moderated so
-non-subscribers can post but messages will be delayed, possibly up to
-48 hours (or longer in case of holidays), until the moderator approves
-your message.
+@value{tramp}'s mailing list is moderated but even non-subscribers can
+post for moderator approval. Sometimes this approval step may take as
+long as 48 hours due to public holidays.
-The mailing list is at @email{tramp-devel@@gnu.org}. Messages sent to
-this address go to all the subscribers. This is @emph{not} the address
-to send subscription requests to.
+@email{tramp-devel@@gnu.org} is the mailing list. Messages sent to
+this address go to all the subscribers. This is @emph{not} the
+address to send subscription requests to.
-Subscribing to the list is performed via
-@uref{http://lists.gnu.org/mailman/listinfo/tramp-devel/,
-the @value{tramp} Mail Subscription Page}.
+To subscribe to the mailing list, visit:
+@uref{http://lists.gnu.org/mailman/listinfo/tramp-devel/, the
+@value{tramp} Mail Subscription Page}.
@ifset emacs
@ifset installchapter
-Before sending a bug report, you could check whether @value{tramp}
-works at all. Run the test suite on your local host, @ref{Testing}.
+Before sending a bug report, run the test suite first @ref{Testing}.
@end ifset
@end ifset
@findex tramp-bug
-To report a bug in @value{tramp}, you should execute @kbd{M-x
-tramp-bug}. This will automatically generate a buffer with the details
-of your system and @value{tramp} version.
-
-When submitting a bug report, please try to describe in excruciating
-detail the steps required to reproduce the problem, the setup of the
-remote host and any special conditions that exist. You should also
-check that your problem is not described already in @xref{Frequently
+Check if the bug or problem is already addressed in @xref{Frequently
Asked Questions}.
-If you can identify a minimal test case that reproduces the problem,
-include that with your bug report. This will make it much easier for
-the development team to analyze and correct the problem.
+Run @kbd{M-x tramp-bug} to generate a buffer with details of the
+system along with the details of the @value{tramp}
+installation. Please include these details with the bug report.
+
+The bug report must describe in as excruciating detail as possible the
+steps required to reproduce the problem. These details must include
+the setup of the remote host and any special or unique conditions that
+exist.
+
+Include a minimal test case that reproduces the problem. This will
+help the development team find the best solution and avoid unrelated
+detours.
-Sometimes, there might be also problems due to Tramp caches. Flush
-all caches before running the test, @ref{Cleanup remote connections}.
+To exclude cache-related problems, flush all caches before running the
+test, @ref{Cleanup remote connections}.
-Before reporting the bug, you should set the verbosity level to 6
-(@pxref{Traces and Profiles, Traces}) in the @file{~/.emacs} file and
-repeat the bug. Then, include the contents of the @file{*tramp/foo*}
-and @file{*debug tramp/foo*} buffers in your bug report. A verbosity
-level greater than 6 will produce a very huge debug buffer, which is
-mostly not necessary for the analysis.
+When including @value{tramp}'s messages in the bug report, increase
+the verbosity level to 6 (@pxref{Traces and Profiles, Traces}) in the
+@file{~/.emacs} file before repeating steps to the bug. Include the
+contents of the @file{*tramp/foo*} and @file{*debug tramp/foo*}
+buffers with the bug report.
-Please be aware that, with a verbosity level of 6 or greater, the
+@strong{Note} that a verbosity level greater than 6 is not necessary
+at this stage. Also note that a verbosity level of 6 or greater, the
contents of files and directories will be included in the debug
-buffer. Passwords you've typed will never be included there.
+buffer. Passwords typed in @value{tramp} will never be included
+there.
@node Frequently Asked Questions
@itemize @bullet
@item
-Where can I get the latest @value{tramp}?
+Where is the latest @value{tramp}?
-@value{tramp} is available under the URL below.
+@value{tramp} is available at the GNU URL:
@noindent
@uref{ftp://ftp.gnu.org/gnu/tramp/}
@noindent
-There is also a Savannah project page.
+@value{tramp}'s GNU project page is located here:
@noindent
@uref{http://savannah.gnu.org/projects/tramp/}
@item
Which systems does it work on?
-The package has been used successfully on Emacs 22, Emacs 23, Emacs
-24, XEmacs 21 (starting with 21.4), and SXEmacs 22.
+The package works successfully on Emacs 22, Emacs 23, Emacs 24, Emacs
+25, XEmacs 21 (starting with 21.4), and SXEmacs 22.
-The package was intended to work on Unix, and it really expects a
-Unix-like system on the remote end (except the @option{smb} method),
-but some people seemed to have some success getting it to work on MS
-Windows XP/Vista/7 @value{emacsname}.
+While Unix and Unix-like systems are the primary remote targets,
+@value{tramp} has equal success connecting to other platforms, such as
+MS Windows XP/Vista/7.
@item
-How could I speed up @value{tramp}?
+How to speed up @value{tramp}?
-In the backstage, @value{tramp} needs a lot of operations on the
-remote host. The time for transferring data from and to the remote
-host as well as the time needed to perform the operations there count.
-In order to speed up @value{tramp}, one could either try to avoid some
-of the operations, or one could try to improve their performance.
+@value{tramp} does many things in the background, some of which
+depends on network speeds, response speeds of remote hosts, and
+authentication delays. During these operations, @value{tramp}'s
+responsiveness slows down. Some suggestions within the scope of
+@value{tramp}'s settings include:
-Use an external method, like @option{scp}.
+Use an external method, such as @option{scp}, which are faster than
+internal methods.
-Use caching. This is already enabled by default. Information about
-the remote host as well as the remote files are cached for reuse. The
-information about remote hosts is kept in the file specified in
-@code{tramp-persistency-file-name}. Keep this file. If you are
-confident that files on remote hosts are not changed out of
-@value{emacsname}' control, set @code{remote-file-name-inhibit-cache}
-to @code{nil}. Set also @code{tramp-completion-reread-directory-timeout}
-to @code{nil}, @ref{File name completion}.
+Keep the file @code{tramp-persistency-file-name}, which is where
+@value{tramp} caches remote information about hosts and files. Caching
+is enabled by default. Don't disable it.
-Disable version control. If you access remote files which are not
-under version control, a lot of check operations can be avoided by
-disabling VC@. This can be achieved by
+Set @code{remote-file-name-inhibit-cache} to @code{nil} if remote
+files are not independently updated outside @value{tramp}'s control.
+That cache cleanup will be necessary if the remote directories or
+files are updated independent of @value{tramp}.
+
+Set @code{tramp-completion-reread-directory-timeout} to @code{nil} to
+speed up completions, @ref{File name completion}.
+
+Disable version control to avoid delays:
@lisp
(setq vc-ignore-dir-regexp
tramp-file-name-regexp))
@end lisp
-Disable excessive traces. The default trace level of @value{tramp},
-defined in the variable @code{tramp-verbose}, is 3. You should
-increase this level only temporarily, hunting bugs.
-
+Disable excessive traces. Set @code{tramp-verbose} to 3 or lower,
+default being 3. Increase trace levels temporarily when hunting for
+bugs.
@item
@value{tramp} does not connect to the remote host
-When @value{tramp} does not connect to the remote host, there are three
-reasons heading the bug mailing list:
+Three main reasons for why @value{tramp} does not connect to the remote host:
@itemize @minus
@item
Unknown characters in the prompt
-@value{tramp} needs to recognize the prompt on the remote host
-after execution any command. This is not possible when the prompt
-contains unknown characters like escape sequences for coloring. This
-should be avoided on the remote side. @xref{Remote shell setup}. for
-setting the regular expression detecting the prompt.
+@value{tramp} needs a clean recognizable prompt on the remote host for
+accurate parsing. Shell prompts that contain escape sequences for
+coloring cause parsing problems. @ref{Remote shell setup} for
+customizing prompt detection using regular expressions.
-You can check your settings after an unsuccessful connection by
-switching to the @value{tramp} connection buffer @file{*tramp/foo*},
-setting the cursor at the top of the buffer, and applying the expression
+To check if the remote host's prompt is being recognized, use this
+test: switch to @value{tramp} connection buffer @file{*tramp/foo*},
+put the cursor at the top of the buffer, and then apply the following
+expression:
@example
@kbd{M-: (re-search-forward (concat tramp-shell-prompt-pattern "$"))}
@end example
-If it fails, or the cursor is not moved at the end of the buffer, your
-prompt is not recognized correctly.
+If the cursor has not moved to the prompt at the bottom of the buffer,
+then @value{tramp} has failed to recognize the prompt.
-A special problem is the zsh shell, which uses left-hand side and
-right-hand side prompts in parallel. Therefore, it is necessary to
-disable the zsh line editor on the remote host. You shall add to
-@file{~/.zshrc} the following command:
+When using zsh on remote hosts, disable zsh line editor because zsh
+uses left-hand side and right-hand side prompts in parallel. Add the
+following line to @file{~/.zshrc}:
@example
[ $TERM = "dumb" ] && unsetopt zle && PS1='$ '
@end example
-Similar fancy prompt settings are known from the fish shell. Here you
-must add in @file{~/.config/fish/config.fish}:
+When using fish shell on remote hosts, disable fancy formatting by
+adding the following to @file{~/.config/fish/config.fish}:
@example
function fish_prompt
end
@end example
-Furthermore it has been reported, that @value{tramp} (like sshfs,
-incidentally) doesn't work with WinSSHD due to strange prompt settings.
+When using WinSSHD on remote hosts, @value{tramp} do not recognize the
+strange prompt settings.
@item
Echoed characters after login
-When the remote host opens an echoing shell, there might be control
-characters in the welcome message. @value{tramp} tries to suppress
-such echoes via the @command{stty -echo} command, but sometimes this
-command is not reached, because the echoed output has confused
-@value{tramp} already. In such situations it might be helpful to use
-the @option{sshx} or @option{scpx} methods, which allocate a pseudo tty.
-@xref{Inline methods}.
+@value{tramp} suppresses echos from remote hosts with the
+@command{stty -echo} command. But sometimes it is too late to suppress
+welcome messages from the remote host containing harmful control
+characters. Using @option{sshx} or @option{scpx} methods can avoid
+this problem because they allocate a pseudo tty. @xref{Inline
+methods}.
@item
-@value{tramp} doesn't transfer strings with more than 500 characters
-correctly
-
-On some few systems, the implementation of @code{process-send-string}
-seems to be broken for longer strings. It is reported for HP-UX,
-FreeBSD and Tru64 Unix, for example. This case, you should customize
-the variable @code{tramp-chunksize} to 500. For a description how to
-determine whether this is necessary see the documentation of
-@code{tramp-chunksize}.
-
-Additionally, it will be useful to set @code{file-precious-flag} to
-@code{t} for @value{tramp} files. Then the file contents will be
-written into a temporary file first, which is checked for correct
-checksum.
+@value{tramp} stops transferring strings longer than 500 characters
+
+Set @code{tramp-chunksize} to 500 to get around this problem, which is
+related to faulty implementation of @code{process-send-string} on
+HP-UX, FreeBSD and Tru64 Unix systems. Consult the documentation for
+@code{tramp-chunksize} to see when this is necessary.
+
+Set @code{file-precious-flag} to @code{t} for files accessed by
+@value{tramp} so the file contents are checked using checksum by
+first saving to a temporary file.
@ifinfo
@pxref{Saving Buffers, , , elisp}
@end ifinfo
@item
-@value{tramp} does not recognize hung @command{ssh} sessions
-
-When your network connection is down, @command{ssh} sessions might
-hang. @value{tramp} cannot detect it safely, because it still sees a
-running @command{ssh} process. Timeouts cannot be used as well,
-because it cannot be predicted how long a remote command will last,
-for example when copying very large files.
+@value{tramp} does not recognize if a @command{ssh} session hangs
-Therefore, you must configure the @command{ssh} process to die
-in such a case. The following entry in @file{~/.ssh/config} would do
-the job:
+@command{ssh} sessions on the local host hang when the network is
+down. @value{tramp} cannot safely detect such hangs. The network
+configuration for @command{ssh} can be configured to kill such hangs
+with the following command in the @file{~/.ssh/config}:
@example
Host *
@item
-@value{tramp} does not use my @command{ssh} @code{ControlPath}
+@value{tramp} does not use default @command{ssh} @code{ControlPath}
-Your @code{ControlPath} setting will be overwritten by @command{ssh}
-sessions initiated by @value{tramp}. This is because a master
-session, initiated outside @value{emacsname}, could be closed, which
-would stall all other @command{ssh} sessions for that host inside
-@value{emacsname}.
-
-Consequently, if you connect to a remote host via @value{tramp}, you
-might be prompted for a password again, even if you have established
-already an @command{ssh} connection to that host. Further
-@value{tramp} connections to that host, for example in order to run a
-process on that host, will reuse that initial @command{ssh}
-connection.
+@value{tramp} overwrites @code{ControlPath} settings when initiating
+@command{ssh} sessions. @value{tramp} does this to fend off a stall
+if a master session opened outside the @value{emacsname} session is no
+longer open. That is why @value{tramp} prompts for the password again
+even if there is an @command{ssh} already open.
-If your @command{ssh} version supports the @code{ControlPersist}
-option, you could customize the variable
-@code{tramp-ssh-controlmaster-options} to use your @code{ControlPath},
-for example:
+Some @command{ssh} versions support a @code{ControlPersist} option,
+which allows to set the @code{ControlPath} provided the variable
+@code{tramp-ssh-controlmaster-options} is customized as follows:
@lisp
(setq tramp-ssh-controlmaster-options
"-o ControlMaster=auto -o ControlPersist=yes"))
@end lisp
-Note, that "%r", "%h" and "%p" must be encoded as "%%r", "%%h" and
-"%%p", respectively.
+Note how "%r", "%h" and "%p" must be encoded as "%%r", "%%h" and
+"%%p".
-These settings can be suppressed, if they are configured properly in
-your @file{~/.ssh/config}:
+If the @file{~/.ssh/config} is configured appropriately for the above
+behavior, then any changes to @command{ssh} can be suppressed with
+this @code{nil} setting:
@lisp
(setq tramp-use-ssh-controlmaster-options nil)
@item
File name completion does not work with @value{tramp}
-When you log in to the remote host, do you see the output of
-@command{ls} in color? If so, this may be the cause of your problems.
-
-@command{ls} outputs @acronym{ANSI} escape sequences that your terminal
-emulator interprets to set the colors. These escape sequences will
-confuse @value{tramp} however.
-
-In your @file{.bashrc}, @file{.profile} or equivalent on the remote
-host you probably have an alias configured that adds the option
-@option{--color=yes} or @option{--color=auto}.
+@acronym{ANSI} escape sequences from the remote shell may cause errors
+in @value{tramp}'s parsing of remote buffers.
-You should remove that alias and ensure that a new login @emph{does not}
-display the output of @command{ls} in color. If you still cannot use
-file name completion, report a bug to the @value{tramp} developers.
+To test if this is the case, open a remote shell and check if the output
+of @command{ls} is in color.
+To disable @acronym{ANSI} escape sequences from the remote hosts,
+disable @option{--color=yes} or @option{--color=auto} in the remote
+host's @file{.bashrc} or @file{.profile}. Turn this alias on and off
+to see if file name completion works.
@item
-File name completion does not work in large directories
+File name completion does not work in directories with large number of
+files
-@value{tramp} uses globbing for some operations. (Globbing means to use the
-shell to expand wildcards such as @samp{*.c}.) This might create long
-command lines, especially in directories with many files. Some shells
-choke on long command lines, or don't cope well with the globbing
-itself.
+This may be related to globbing, which is the use of shell's ability
+to expand wild card specifications, such as @samp{*.c}. For
+directories with large number of files, globbing might exceed the
+shell's limit on length of command lines and hang. @value{tramp} uses
+globbing.
-If you have a large directory on the remote end, you may wish to execute
-a command like @samp{ls -d * ..?* > /dev/null} and see if it hangs.
-Note that you must first start the right shell, which might be
-@command{/bin/sh}, @command{ksh} or @command{bash}, depending on which
-of those supports tilde expansion.
+To test if globbing hangs, open a shell on the remote host and then
+run @samp{ls -d * ..?* > /dev/null}.
+
+When testing, ensure the remote shell is the same shell
+(@command{/bin/sh}, @command{ksh} or @command{bash}), that
+@value{tramp} uses when connecting to that host.
@item
-How can I get notified when @value{tramp} file transfers are complete?
+How to get notified after @value{tramp} completes file transfers?
-The following snippet can be put in your @file{~/.emacs} file. It
-makes @value{emacsname} beep after reading from or writing to the
-remote host.
+Make @value{emacsname} beep after reading from or writing to the
+remote host with the following code in @file{~/.emacs} file.
@lisp
(defadvice tramp-handle-write-region
@ifset emacs
@item
-I'ld like to get a Visual Warning when working in a sudo:ed context
+How to get a Visual Warning when working with @samp{root} privileges
-When you are working with @samp{root} privileges, it might be useful
-to get an indication in the buffer's modeline. The following code,
-tested with @value{emacsname} 22.1, does the job. You should put it
-into your @file{~/.emacs}:
+Get a modeline indication when working with @samp{root} privileges
+with the following code (tested with @value{emacsname} 22.1) in
+@file{~/.emacs} file:
@lisp
(defun my-mode-line-function ()
@ifset emacs
@item
-I'ld like to see a host indication in the mode line when I'm remote
+How to get host indication in the mode line?
-The following code has been tested with @value{emacsname} 22.1. You
-should put it into your @file{~/.emacs}:
+The following code (tested with @value{emacsname} 22.1) in
+@file{~/.emacs} file shows it:
@lisp
(defconst my-mode-line-buffer-identification
my-mode-line-buffer-identification)))
@end lisp
-Since @value{emacsname} 23.1, the mode line contains an indication if
-@code{default-directory} for the current buffer is on a remote host.
-The corresponding tooltip includes the name of that host. If you
-still want the host name as part of the mode line, you can use the
-example above, but the @code{:eval} clause can be simplified:
+The mode line in @value{emacsname} 23.1 and later versions now
+contains an indication if @code{default-directory} for the current
+buffer is on a remote host. Moreover, the corresponding tool-tip
+shows the remote host name. The above @code{:eval} clause can also be
+simplified to show the host name in the mode line:
@lisp
'(:eval
@ifset emacs
@item
-My remote host does not understand default directory listing options
+Remote host does not understand default options for directory listing
-@value{emacsname} computes the @command{dired} options depending on
-the local host you are working. If your @command{ls} command on the
-remote host does not understand those options, you can change them
-like this:
+@value{emacsname} computes the @command{dired} options based on the
+local host but if the remote host cannot understand the same
+@command{ls} command, then set them with a hook as follows:
@lisp
(add-hook
@item
-There's this @file{~/.sh_history} file on the remote host which keeps
-growing and growing. What's that?
+Why is @file{~/.sh_history} file on the remote host growing?
-Sometimes, @value{tramp} starts @command{ksh} on the remote host for
-tilde expansion. Maybe @command{ksh} saves the history by default.
-@value{tramp} tries to turn off saving the history, but maybe you have
-to help. For example, you could put this in your @file{.kshrc}:
+Due to @command{ksh} saving tilde expansions triggered by
+@value{tramp}, the history file is probably growing rapidly. To fix,
+turn off saving history by putting this shell code in the
+@file{.kshrc} file:
@example
if [ -f $HOME/.sh_history ] ; then
fi
@end example
-Furthermore, if you use an @option{ssh}-based method, you could add
-the following line to your @file{~/.ssh/environment} file:
+For @option{ssh}-based method, add the following line to your
+@file{~/.ssh/environment} file:
@example
HISTFILE=/dev/null
@end example
-@item There are longish file names to type. How to shorten this?
+@item
+How to shorten long file names when typing in @value{tramp}?
-Let's say you need regularly access to @file{@trampfn{ssh, news,
-news.my.domain, /opt/news/etc}}, which is boring to type again and
-again. The following approaches can be mixed:
+Adapt several of these approaches to reduce typing. If the full name
+is @file{@trampfn{ssh, news, news.my.domain, /opt/news/etc}}, then:
@enumerate
-@item Use default values for method and user name:
+@item
+Use default values for method name and user name:
You can define default methods and user names for hosts,
(@pxref{Default Method}, @pxref{Default User}):
tramp-default-user "news")
@end lisp
-The file name left to type would be
-@kbd{C-x C-f @trampfn{, , news.my.domain, /opt/news/etc}}.
+The reduced typing: @kbd{C-x C-f @trampfn{, , news.my.domain, /opt/news/etc}}.
-Note that there are some useful settings already. Accessing your
-local host as @samp{root} user, is possible just by @kbd{C-x C-f
+@strong{Note} that there are some useful shortcuts already. Accessing
+your local host as @samp{root} user, is possible just by @kbd{C-x C-f
@trampfn{su, , ,}}.
-@item Use configuration possibilities of your method:
+@item
+Use configuration options of the access method:
-Several connection methods (i.e., the programs used) offer powerful
-configuration possibilities (@pxref{Customizing Completion}). In the
-given case, this could be @file{~/.ssh/config}:
+Programs used for access methods already offer powerful configurations
+(@pxref{Customizing Completion}). For @option{ssh}, configure the
+file @file{~/.ssh/config}:
@example
Host xy
User news
@end example
-The file name left to type would be @kbd{C-x C-f @trampfn{ssh, , xy,
-/opt/news/etc}}. Depending on files in your directories, it is even
-possible to complete the host name with @kbd{C-x C-f
+The reduced typing: @kbd{C-x C-f @trampfn{ssh, , xy, /opt/news/etc}}.
+
+Depending on the number of files in the directories, host names
+completion can further reduce key strokes: @kbd{C-x C-f
@value{prefix}ssh@value{postfixhop}x @key{TAB}}.
-@item Use environment variables:
+@item
+Use environment variables to expand long strings
-File names typed in the minibuffer can be expanded by environment
-variables. You can set them outside @value{emacsname}, or even with
-Lisp:
+For long file names, set up environment variables that are expanded in
+the minibuffer. Environment variables are set either outside
+@value{emacsname} or inside @value{emacsname} with Lisp:
@lisp
(setenv "xy" "@trampfn{ssh, news, news.my.domain, /opt/news/etc/}")
@end lisp
-Then you need simply to type @kbd{C-x C-f $xy @key{RET}}, and here you
-are. The disadvantage is that you cannot edit the file name, because
+The reduced typing: @kbd{C-x C-f $xy @key{RET}}.
+
+@strong{Note} that file name cannot be edited here because the
environment variables are not expanded during editing in the
minibuffer.
@item Define own keys:
-You can define your own key sequences in @value{emacsname}, which can
-be used instead of @kbd{C-x C-f}:
+Redefine another key sequence in @value{emacsname} for @kbd{C-x C-f}:
@lisp
(global-set-key
"@trampfn{ssh, news, news.my.domain, /opt/news/etc/}"))))
@end lisp
-Simply typing @kbd{C-x C-y} would initialize the minibuffer for
-editing with your beloved file name.
+Simply typing @kbd{C-x C-y} would prepare minibuffer editing of file
+name.
-See also @uref{http://www.emacswiki.org/cgi-bin/wiki/TrampMode, the
-Emacs Wiki} for a more comprehensive example.
+See @uref{http://www.emacswiki.org/cgi-bin/wiki/TrampMode, the Emacs
+Wiki} for a more comprehensive example.
-@item Define own abbreviation (1):
+@item
+Define own abbreviation (1):
-It is possible to define an own abbreviation list for expanding file
-names:
+Abbreviation list expansion can be used to reduce typing long file names:
@lisp
(add-to-list
'("^/xy" . "@trampfn{ssh, news, news.my.domain, /opt/news/etc/}"))
@end lisp
-This shortens the file opening command to @kbd{C-x C-f /xy
-@key{RET}}. The disadvantage is, again, that you cannot edit the file
-name, because the expansion happens after entering the file name only.
+The reduced typing: @kbd{C-x C-f /xy @key{RET}}.
+
+@strong{Note} that file name cannot be edited here because the
+environment variables are not expanded during editing in the
+minibuffer.
-@item Define own abbreviation (2):
+@item
+Define own abbreviation (2):
-The @code{abbrev-mode} gives more flexibility for editing the
+The @code{abbrev-mode} gives additional flexibility for editing in the
minibuffer:
@lisp
(expand-abbrev))
@end lisp
-After entering @kbd{C-x C-f xy @key{TAB}}, the minibuffer is
-expanded, and you can continue editing.
+The reduced typing: @kbd{C-x C-f xy @key{TAB}}.
+
+The minibuffer expands for further editing.
@item Use bookmarks:
-Bookmarks can be used to visit Tramp files or directories.
+Use bookmarks to save Tramp file names.
@ifinfo
-@pxref{Bookmarks, , , @value{emacsdir}}
+@pxref{Bookmarks, , , @value{emacsdir}}.
@end ifinfo
-When you have opened @file{@trampfn{ssh, news, news.my.domain,
-/opt/news/etc/}}, you should save the bookmark via
+Upon visiting a location with @value{tramp}, save it as a bookmark with
@ifset emacs
@kbd{@key{menu-bar} @key{edit} @key{bookmarks} @key{set}}.
@end ifset
@kbd{@key{menu-bar} @key{view} @key{bookmarks} @key{set}}.
@end ifset
-Later on, you can always navigate to that bookmark via
+To revisit that bookmark:
@ifset emacs
@kbd{@key{menu-bar} @key{edit} @key{bookmarks} @key{jump}}.
@end ifset
remembers visited places.
@ifinfo
@ifset emacs
-@pxref{File Conveniences, , , @value{emacsdir}}
+@pxref{File Conveniences, , , @value{emacsdir}}.
@end ifset
@ifset xemacs
-@pxref{recent-files, , , edit-utils}
+@pxref{recent-files, , , edit-utils}.
@end ifset
@end ifinfo
-You could keep remote file names in the recent list without checking
-their readability through a remote access:
+Keep remote file names in the recent list without have to check for
+their accessibility through remote access:
@lisp
@ifset emacs
@end ifset
@end lisp
-The list of files opened recently is reachable via
+Reaching recently opened files:
@ifset emacs
@kbd{@key{menu-bar} @key{file} @key{Open Recent}}.
@end ifset
@ifset emacs
@item Use filecache:
-@file{filecache} remembers visited places. Add the directory into
-the cache:
+Since @file{filecache} remembers visited places, add the remote
+directory to the cache:
@lisp
(eval-after-load "filecache"
"@trampfn{ssh, news, news.my.domain, /opt/news/etc/}"))
@end lisp
-Whenever you want to load a file, you can enter @kbd{C-x C-f
-C-@key{TAB}} in the minibuffer. The completion is done for the given
-directory.
+Then use directory completion in the minibuffer with @kbd{C-x C-f
+C-@key{TAB}}.
@end ifset
@ifset emacs
@item Use bbdb:
@file{bbdb} has a built-in feature for @value{ftppackagename} files,
-which works also for @value{tramp}.
+which also works for @value{tramp} file names.
@ifinfo
-@pxref{bbdb-ftp, Storing FTP sites in the BBDB, , bbdb}
+@pxref{bbdb-ftp, Storing FTP sites in the BBDB, , bbdb}.
@end ifinfo
-You need to load @file{bbdb}:
+Load @file{bbdb} in @value{emacs}:
@lisp
(require 'bbdb)
(bbdb-initialize)
@end lisp
-Then you can create a BBDB entry via @kbd{M-x bbdb-create-ftp-site}.
-Because BBDB is not prepared for @value{tramp} syntax, you must
-specify a method together with the user name when needed. Example:
+Create a BBDB entry with @kbd{M-x bbdb-create-ftp-site}. Then specify
+a method and user name where needed. Examples:
@example
@kbd{M-x bbdb-create-ftp-site @key{RET}}
@b{Additional Comments:} @key{RET}
@end example
-When you have opened your BBDB buffer, you can access such an entry by
-pressing the key @key{F}.
+In BBDB buffer, access an entry by pressing the key @key{F}.
@end ifset
@end enumerate
-I would like to thank all @value{tramp} users who have contributed to
-the different recipes!
+Thanks to @value{tramp} users for contributing to these recipes.
+@item
+Why saved multi-hop file names do not work in a new @value{emacsname}
+session?
-@item I have saved @value{tramp} file names as indicated. But it
-doesn't work in a new @value{emacsname} session!
-
-If you have saved an ad-hoc multi-hop @value{tramp} file name
-(@pxref{Ad-hoc multi-hops}) via bookmarks, recent files,
+When saving ad-hoc multi-hop @value{tramp} file names (@pxref{Ad-hoc
+multi-hops}) via bookmarks, recent files,
@ifset emacs
filecache, bbdb,
@end ifset
-or another package, you must use the full ad-hoc file name including
-all hops, like @file{@trampfn{ssh, bird,
+or another package, use the full ad-hoc file name including all hops,
+like @file{@trampfn{ssh, bird,
bastion|ssh@value{postfixhop}news.my.domain, /opt/news/etc}}.
-Alternatively, if you save only the abbreviated multi-hop file name
+Alternatively, when saving abbreviated multi-hop file names
@file{@trampfn{ssh, news, news.my.domain, /opt/news/etc}}, the custom
-option @code{tramp-save-ad-hoc-proxies} must be set to a to a
-non-@code{nil} value.
+option @code{tramp-save-ad-hoc-proxies} must be set non-@code{nil}
+value.
@ifset emacs
@item
-How can I use @value{tramp} to connect to a remote @value{emacsname}
-session?
+How to connect to a remote @value{emacsname} session using @value{tramp}?
-You can configure Emacs Client doing this.
+Configure Emacs Client
@ifinfo
-@xref{Emacs Server, , , @value{emacsdir}}.
+(@pxref{Emacs Server, , , @value{emacsdir}}).
@end ifinfo
-On the remote host, you start the Emacs Server:
+Then on the remote host, start the Emacs Server:
@lisp
(require 'server)
(server-start)
@end lisp
-Make sure that the result of @code{(system-name)} can be resolved on
-your local host; otherwise you might use a hard coded IP address.
+If @code{(system-name)} of the remote host cannot be resolved on the
+local host, use IP address instead.
+
+Copy from the remote host the resulting file
+@file{~/.emacs.d/server/server} to the local host, to the same
+location.
-The resulting file @file{~/.emacs.d/server/server} must be copied to
-your local host, at the same location. You can call then the Emacs
-Client from the command line:
+Then start Emacs Client from the command line:
@example
emacsclient @trampfn{ssh, user, host, /file/to/edit}
@end example
-@code{user} and @code{host} shall be related to your local host.
+@code{user} and @code{host} refer to the local host.
-If you want to use Emacs Client also as editor for other programs, you
-could write a script @file{emacsclient.sh}:
+To make Emacs Client an editor for other programs, use a wrapper
+script @file{emacsclient.sh}:
@example
#!/bin/sh
emacsclient @trampfn{ssh, $(whoami), $(hostname --fqdn), $1}
@end example
-Then you must set the environment variable @env{EDITOR} pointing to
-that script:
+Then change the environment variable @env{EDITOR} to point to the
+wrapper script:
@example
export EDITOR=/path/to/emacsclient.sh
@item
-There are packages which call @value{tramp} although I haven't entered
-a remote file name ever. I dislike it, how could I disable it?
+How to disable other packages from calling @value{tramp}?
-In general, @value{tramp} functions are used only when
-you apply remote file name syntax. However, some packages enable
-@value{tramp} on their own.
+There are packages that call @value{tramp} without the user ever
+entering a remote file name. Even without applying a remote file
+syntax, some packages enable @value{tramp} on their own. How can users
+disable such features.
@itemize @minus
@item
@file{ido.el}
-You could disable @value{tramp} file name completion:
+Disable @value{tramp} file name completion:
@lisp
(custom-set-variables
@item
@file{rlogin.el}
-You could disable remote directory tracking mode:
+Disable remote directory tracking mode:
@lisp
(rlogin-directory-tracking-mode -1)
@item
-How can I disable @value{tramp} at all?
-
-Shame on you, why did you read until now?
+How to disable @value{tramp}?
@itemize @minus
@ifset emacs
@item
-If you just want to have @value{ftppackagename} as default remote
-files access package, you should apply the following code:
+To keep @value{ftppackagename} as default the remote files access
+package, set this in @file{.emacs}:
@lisp
(setq tramp-default-method "ftp")
@end ifset
@item
-In order to disable
+To disable both
@ifset emacs
@value{tramp} (and @value{ftppackagename}),
@end ifset
@ifset xemacs
@value{tramp},
@end ifset
-you must set @code{tramp-mode} to @code{nil}:
+set @code{tramp-mode} to @code{nil} in @file{.emacs}.
@lisp
(setq tramp-mode nil)
@end lisp
@item
-Unloading @value{tramp} can be achieved by applying @kbd{M-x
-tramp-unload-tramp}.
+To unload @value{tramp}, type @kbd{M-x tramp-unload-tramp}.
@ifset emacs
-This resets also the @value{ftppackagename} plugins.
+Unloading @value{tramp} resets @value{ftppackagename} plugins also.
@end ifset
@end itemize
@end itemize
@chapter How file names, directories and localnames are mangled and managed.
@menu
-* Localname deconstruction:: Breaking a localname into its components.
+* Localname deconstruction:: Splitting a localname into its component parts.
@ifset emacs
-* External packages:: Integration with external Lisp packages.
+* External packages:: Integrating with external Lisp packages.
@end ifset
@end menu
@node Localname deconstruction
-@section Breaking a localname into its components
-
-@value{tramp} file names are somewhat different, obviously, to ordinary file
-names. As such, the lisp functions @code{file-name-directory} and
-@code{file-name-nondirectory} are overridden within the @value{tramp}
-package.
+@section Splitting a localname into its component parts
-Their replacements are reasonably simplistic in their approach. They
-dissect the file name, call the original handler on the localname and
-then rebuild the @value{tramp} file name with the result.
+@value{tramp} package redefines lisp functions
+@code{file-name-directory} and @code{file-name-nondirectory} to
+accommodate the unique file naming syntax that @value{tramp} requires.
-This allows the platform specific hacks in the original handlers to take
-effect while preserving the @value{tramp} file name information.
+The replacements dissect the file name, use the original handler for
+the localname, take that result, and then re-build the @value{tramp}
+file name. By relying on the original handlers for localnames,
+@value{tramp} benefits from platform specific hacks to the original
+handlers.
@ifset emacs
@node External packages
-@section Integration with external Lisp packages
+@section Integrating with external Lisp packages
@subsection File name completion.
-While reading file names in the minibuffer, @value{tramp} must decide
-whether it completes possible incomplete file names, or not. Imagine
-there is the following situation: You have typed @kbd{C-x C-f
-@value{prefix}ssh@value{postfixhop} @key{TAB}}. @value{tramp} cannot
-know, whether @option{ssh} is a method or a host name. It checks
-therefore the last input character you have typed. If this is
-@key{TAB}, @key{SPACE} or @kbd{?}, @value{tramp} assumes that you are
-still in file name completion, and it does not connect to the possible
-remote host @option{ssh}.
-
-External packages, which use other characters for completing file names
-in the minibuffer, must signal this to @value{tramp}. For this case,
-the variable @code{non-essential} can be bound temporarily to
-a non-@code{nil} value.
+For name completions in the minibuffer, @value{tramp} depends on the
+last input character to decide whether to look for method name
+completion or host name completion. For example, @kbd{C-x C-f
+@value{prefix}ssh@value{postfixhop} @key{TAB}} is not entirely clear
+if @option{ssh} is a method or a host name. But if the last input
+character was either @key{TAB}, @key{SPACE} or @kbd{?}, then
+@value{tramp} favors file name completion over host name completion.
+
+What about external packages using other characters to trigger file
+name completions? They must somehow signal this to @value{tramp}. Use
+the variable @code{non-essential} temporarily and bind it to
+non-@code{nil} value.
@lisp
(let ((non-essential t))
@subsection File attributes cache.
-When @value{tramp} runs remote processes, files on the remote host
-could change their attributes. Consequently, @value{tramp} must flush
-its complete cache keeping attributes for all files of the remote host
-it has seen so far.
+Keeping a local cache of remote file attributes in sync with the
+remote host is a time-consuming operation. Flushing and re-querying
+these attributes can tax @value{tramp} to a grinding halt on busy
+remote servers.
-This is a performance degradation, because the lost file attributes
-must be recomputed when needed again. In cases where the caller of
-@code{process-file} knows that there are no file attribute changes, it
-should let-bind the variable @code{process-file-side-effects} to
-@code{nil}. Then @value{tramp} won't flush the file attributes cache.
+To get around these types of slow-downs in @value{tramp}'s
+responsiveness, set the @code{process-file-side-effects} to @code{nil}
+to stop @value{tramp} from flushing the cache. This is helpful in
+situations where callers to @code{process-file} know there are no file
+attribute changes. The let-bind form to accomplish this:
@lisp
(let (process-file-side-effects)
@dots{})
@end lisp
-For asynchronous processes, @value{tramp} flushes the file attributes
-cache via a process sentinel. If the caller of
-@code{start-file-process} knows that there are no file attribute
-changes, it should set the process sentinel to the default. In cases
-where the caller defines its own process sentinel, @value{tramp}'s process
+For asynchronous processes, @value{tramp} uses a process sentinel to
+flush file attributes cache. When callers to @code{start-file-process}
+know beforehand no file attribute changes are expected, then the
+process sentinel should be set to the default state. In cases where
+the caller defines its own process sentinel, @value{tramp}'s process
sentinel is overwritten. The caller can still flush the file
attributes cache in its process sentinel with this code:
(dired-uncache remote-directory))
@end lisp
-@code{remote-directory} shall be the root directory, where file
-attribute changes can happen during the process lifetime.
-@value{tramp} traverses all subdirectories, starting at this
-directory. Often, it is sufficient to use @code{default-directory} of
-the process buffer as root directory.
+Since @value{tramp} traverses subdirectories starting with the
+root-directory, it is most likely sufficient to make the
+@code{default-directory} of the process buffer as the root directory.
@end ifset
@node Traces and Profiles
@chapter How to Customize Traces
-All @value{tramp} messages are raised with a verbosity level. The
-verbosity level can be any number between 0 and 10. Only messages with
-a verbosity level less than or equal to @code{tramp-verbose} are
-displayed.
+@value{tramp} messages are raised with verbosity levels ranging from 0
+to 10. @value{tramp} does not display all messages; only those with a
+verbosity level less than or equal to @code{tramp-verbose}.
The verbosity levels are
@*@indent @w{ 9} test commands
@*@indent @w{10} traces (huge)
-When @code{tramp-verbose} is greater than or equal to 4, the messages
-are also written into a @value{tramp} debug buffer. This debug buffer
-is useful for analyzing problems; sending a @value{tramp} bug report
-should be done with @code{tramp-verbose} set to a verbosity level of at
-least 6 (@pxref{Bug Reports}).
+With @code{tramp-verbose} greater than or equal to 4, messages are
+also written to a @value{tramp} debug buffer. Such debug buffers are
+essential to bug and problem analyses. For @value{tramp} bug reports,
+set the @code{tramp-verbose} level to 6 (@pxref{Bug Reports}).
The debug buffer is in
@ifinfo
@ifnotinfo
Outline Mode.
@end ifnotinfo
-That means, you can change the level of messages to be viewed. If you
-want, for example, see only messages up to verbosity level 5, you must
-enter @kbd{C-u 6 C-c C-q}.
+In this buffer, messages can be filtered by their level. To see
+messages up to verbosity level 5, enter @kbd{C-u 6 C-c C-q}.
@ifinfo
-Other keys for navigating are described in
+Other navigation keys are described in
@ref{Outline Visibility, , , @value{emacsdir}}.
@end ifinfo
-@value{tramp} errors are handled internally in order to raise the
-verbosity level 1 messages. When you want to get a Lisp backtrace in
-case of an error, you need to set both
+@value{tramp} handles errors internally. But to get a Lisp backtrace,
+both the error and the signal have to be set as follows:
@lisp
(setq debug-on-error t
debug-on-signal t)
@end lisp
-Sometimes, it might be even necessary to step through @value{tramp}
-function call traces. Such traces are enabled by the following code:
+To enable stepping through @value{tramp} function call traces, they
+have to be specifically enabled as shown in this code:
@lisp
(require 'trace)
(untrace-function 'tramp-gw-basic-authentication)
@end lisp
-The function call traces are inserted in the buffer
-@file{*trace-output*}. @code{tramp-read-passwd} and
-@code{tramp-gw-basic-authentication} shall be disabled when the
-function call traces are added to @value{tramp}, because both
-functions return password strings, which should not be distributed.
+The buffer @file{*trace-output*} contains the output from the function
+call traces. Disable @code{tramp-read-passwd} and
+@code{tramp-gw-basic-authentication} to stop password strings from
+being written to @file{*trace-output*}.
@node Issues
@itemize @bullet
@item The uuencode method does not always work.
-Due to the design of @value{tramp}, the encoding and decoding programs
-need to read from stdin and write to stdout. On some systems,
-@command{uudecode -o -} will read stdin and write the decoded file to
-stdout, on other systems @command{uudecode -p} does the same thing.
-But some systems have uudecode implementations which cannot do this at
-all---it is not possible to call these uudecode implementations with
-suitable parameters so that they write to stdout.
+@command{uudecode} on some systems cannot write to stdout, but
+@value{tramp} depends on encoding and decoding programs to be able to
+read from stdin and write to stdout.
-Of course, this could be circumvented: the @code{begin foo 644} line
-could be rewritten to put in some temporary file name, then
-@command{uudecode} could be called, then the temp file could be
-printed and deleted.
+We can find ways to circumvent @command{uudecode}'s ability to write
+to stdout, such as writing to a temporary file and then piping that to
+stdout.
-But I have decided that this is too fragile to reliably work, so on some
-systems you'll have to do without the uuencode methods.
+But I have decided not to implement workarounds as they are too
+fragile to work reliably. Some on systems, @value{tramp} will not have
+uuencode method.
@item The @value{tramp} file name syntax differs between Emacs and XEmacs.
The Emacs maintainers wish to use a unified file name syntax for
-Ange-FTP and @value{tramp} so that users don't have to learn a new
-syntax. It is sufficient to learn some extensions to the old syntax.
+Ange-FTP and @value{tramp} so that users don't have to learn yet
+another syntax though it is okay to learn new extensions.
-For the XEmacs maintainers, the problems caused from using a unified
-file name syntax are greater than the gains. The XEmacs package system
-uses EFS for downloading new packages. So, obviously, EFS has to be
-installed from the start. If the file names were unified, @value{tramp}
-would have to be installed from the start, too.
+For the XEmacs maintainers, the disruption from a unified file name
+syntax are not worth the gains. Firstly, the XEmacs package system
+relies on EFS for downloading new packages and therefore is already
+installed. On the other hand, @value{tramp} is not installed by
+default in XEmacs. Unifying will require @value{tramp} installed from
+the start.
@ifset xemacs
-@strong{Note:} If you'd like to use a similar syntax like
-@value{ftppackagename}, you need the following settings in your init
-file:
+@strong{Note:} To make the syntax similar to @value{ftppackagename},
+make this change to the init file:
@lisp
(setq tramp-unified-filenames t)
(require 'tramp)
@end lisp
-The autoload of the @value{emacsname} @value{tramp} package must be
-disabled. This can be achieved by setting file permissions @code{000}
-to the files @file{@dots{}/xemacs-packages/lisp/tramp/auto-autoloads.el*}.
+To disable auto loading @value{emacsname} @value{tramp} package, set
+file permissions of
+@file{@dots{}/xemacs-packages/lisp/tramp/auto-autoloads.el*} to
+@code{000}.
-In case of unified file names, all @value{emacsname} download sites are
-added to @code{tramp-default-method-alist} with default method
-@option{ftp} @xref{Default Method}. These settings shouldn't be
-touched for proper working of the @value{emacsname} package system.
+When using unified file names, @value{emacsname} download sites are
+added to @code{tramp-default-method-alist} with default method of
+@option{ftp} @xref{Default Method} for proper working of the
+@value{emacsname} package system.
The syntax for unified file names is described in the @value{tramp} manual
for @value{emacsothername}.
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