Expands to the value bound to @code{var}. This is the main way to use
variables in command invocations.
+@item $"var"
+@item $'var'
+Expands to the value bound to @code{var}. This is useful to
+disambiguate the variable name when concatenating it with another
+value, such as @samp{$"var"-suffix}.
+
@item $#var
Expands to the length of the value bound to @code{var}. Raises an error
if the value is not a sequence
Returns the output of @command{command}, which can be any valid Eshell
command invocation, and may even contain expansions.
+@item $<command>
+As with @samp{$@{command@}}, evaluates the Eshell command invocation
+@command{command}, but writes the output to a temporary file and
+returns the file name.
+
@item $var[i]
Expands to the @code{i}th element of the value bound to @code{var}. If
the value is a string, it will be split at whitespace to make it a list.
;;
;; "-" is a valid part of a variable name.
;;
-;; $<MYVAR>-TOO
+;; $\"MYVAR\"-TOO
+;; $'MYVAR'-TOO
;;
;; Only "MYVAR" is part of the variable name in this case.
;;
;; Returns the value of an eshell subcommand. See the note above
;; regarding Lisp evaluations.
;;
+;; $<command>
+;;
+;; Evaluates an eshell subcommand, redirecting the output to a
+;; temporary file, and returning the file name.
+;;
;; $ANYVAR[10]
;;
;; Return the 10th element of ANYVAR. If ANYVAR's value is a string,
Possible options are:
NAME an environment or Lisp variable value
- <LONG-NAME> disambiguates the length of the name
+ \"LONG-NAME\" disambiguates the length of the name
+ 'LONG-NAME' as above
{COMMAND} result of command is variable's value
- (LISP-FORM) result of Lisp form is variable's value"
+ (LISP-FORM) result of Lisp form is variable's value
+ <COMMAND> write the output of command to a temporary file;
+ result is the file name"
(cond
((eq (char-after) ?{)
(let ((end (eshell-find-delimiter ?\{ ?\})))