Grep

Helm grep is a Helm implementation of the grep command, which searches a text file for lines matching a regular expression.

Features include:

• Incremental
• Recursive
• Faster than Emacs grep
• Supports wildcards
• Respects grep-fine-ignored-files and grep-find-ignored-directories variables

Usage

From helm-find-files (<helm-prefix> C-x C-f), open the action menu with TAB and choose grep. A prefix argument will launch recursive grep, or .

You can also launch grep directly with (C-u) M-g s without switching to the action menu.

Single file

Just launch grep, it will search in file at point. If the file is a directory, grep will search recursively in all files of in the directory like:

grep -nH -e pattern *

Marked files

To grep marked files, just mark some files with C-<space> and launch grep. Marked files can be from different directories.

Recursive

Go to the root of the directory you want to grep in, then hit TAB to open the action menu and choose grep with a prefix argument (C-u).

You will be prompted for types of files to search. Wildcard syntax like \*.el (which searches only files ending in . el) is allowed.

By default, the extension of the file at point is used when the cursor is on a file name. If the cursor is at root of a directory, all the file name extensions found in the directory and not matching the variable grep-find-ignored-files are inserted into the prompt.

Persistent action

Persistent action in a Helm grep buffer (C-z) will bring up the buffer corresponding to the file being grepped.

C-u C-z will record the location in the mark ring. If you want to come back later to the grepped location, there is no need to grep again; you can find the locations in the mark ring.

Accessing the mark ring in Emacs is very inconvenient. Fortunately, the helm-all-mark-rings command (in the menu, Tools > Helm > Tools > Browse Mark Ring) brings up a list of all mark rings, both local and global.

Highlight results

By default, Helm applies its own highlights to matched items. However, it may be better to use the backend to highlight result with ANSI sequences.

This can be done by customizing the helm-grep-default-command variable. See the docstring of helm-grep-default-command for more information.

grep

(setq helm-grep-default-command
      "grep --color=always -d skip %e -n%cH -e %p %f"
      helm-grep-default-recurse-command
      "grep --color=always -d recurse %e -n%cH -e %p %f")

Note: The non-matched part of the resulting lines in grep will be hidden when using --color=always. To fix this you have to set the environmental variable GREP_COLORS for Emacs:

(setenv "GREP_COLORS" "ms=30;43:mc=30;43:sl=01;37:cx=:fn=35:ln=32:bn=32:se=36")

This will colorize matched items in black/yellow.

ack-grep

(setq helm-grep-default-command
      "ack-grep -Hn --smart-case --no-group %e %p %f"
      helm-grep-default-recurse-command
      "ack-grep -H --smart-case --no-group %e %p %f")

git-grep

(setq helm-ls-git-grep-command
      "git grep -n%cH --color=always --full-name -e %p %f")

The color of git-grep can be customized from global .gitconfig file.

Save session

If you want to save the results of your grep session, doing C-x C-s will save your grep results in a helm-grep-mode buffer.

Tip:

• You can save multiple Helm grep buffers with different names.
• If you haven’t saved your grep session in a named buffer, you can still retrieve the last session with helm-resume.

Editing the helm-grep-mode buffer is possible with wgrep. Saving this buffer will apply changes to the corresponding files.

Other search tools

Helm grep supports other tools like ag, pt, and git-grep.

ag, pt

Both ag and pt can be used with helm-do-grep-ag. The variable helm-grep-ag-command controls the exact command used.

git-grep

git-grep can be used with helm-grep-do-git-grep.

TRAMP

Helm grep works with TRAMP (you can grep a file on a remote host or in su/sudo methods), but TRAMP has poor support for multiple processes launched with short delays (< 5 seconds) between them.

Therefore, I recommend that that you suspend Helm updates with =C-!= while you write your regexp. Once done, hit again C-! to restart Helm updates.

If you don’t do that, Helm grep should still work, but it will be slow and may result in occasional failures.

Platforms

OS X

Apple OS X users need a version of grep that accepts --exclude-dir. Install it from Homebrew with:

brew tap homebrew/dupes
brew install homebrew/dupes/grep

You should also set helm-grep-default-command to use ggrep instead of grep.

Windows

Windows users need grep version 2.5.4 of Gnuwin32. This version should accept the --exclude-dir option.