29.15.4.3 Shell History References

Various shells including csh and bash support history references that begin with `!' and `^'. Shell mode recognizes these constructs, and can perform the history substitution for you.

If you insert a history reference and type <TAB>, this searches the input history for a matching command, performs substitution if necessary, and places the result in the buffer in place of the history reference. For example, you can fetch the most recent command beginning with `mv' with ! m v <TAB>. You can edit the command if you wish, and then resubmit the command to the shell by typing <RET>.

Shell mode can optionally expand history references in the buffer when you send them to the shell. To request this, set the variable comint-input-autoexpand to input. You can make <SPC> perform history expansion by binding <SPC> to the command comint-magic-space.

Shell mode recognizes history references when they follow a prompt. Normally, any text output by a program at the beginning of an input line is considered a prompt. However, if the variable comint-use-prompt-regexp-instead-of-fields is non-nil, then Comint mode uses a regular expression to recognize prompts. In general, the variable comint-prompt-regexp specifies the regular expression; Shell mode uses the variable shell-prompt-pattern to set up comint-prompt-regexp in the shell buffer.