* lisp/simple.el (shell-command): Mention that COMMAND is prompted
for. (Bug#22926)
"Execute string COMMAND in inferior shell; display output, if any.
With prefix argument, insert the COMMAND's output at point.
+Interactively, prompt for COMMAND in the minibuffer.
+
If COMMAND ends in `&', execute it asynchronously.
The output appears in the buffer `*Async Shell Command*'.
That buffer is in shell mode. You can also use