Function: grep

Run grep, with user-specified args, and collect output in a buffer.
While grep runs asynchronously, you can use C-x ` (M-x next-error),
Uses keymap `grep-mode-map', which is not currently defined.
M-x compile-goto-error in the *grep* buffer, to go to the lines where grep found
matches. To kill the grep job before it finishes, type M-x kill-compilation.

For doing a recursive `grep', see the `rgrep' command. For running
`grep' in a specific directory, see `lgrep'.

This command uses a special history list for its COMMAND-ARGS, so you
can easily repeat a grep command.

A prefix argument says to default the argument based upon the current
tag the cursor is over, substituting it into the last grep command
in the grep command history (or into `grep-command' if that history list is empty). (fn COMMAND-ARGS)