search replace with Emacs

Search (and replace) is something I do so much in emacs, I want to share my typical workflow for it.

search in buffer(s)

For this purpose, I like to use swiper 1 which I bind to C-s.

swiper searches inside current buffer and list all matches in minibuffer. To search in all open buffers, use swiper-all instead.

Sometimes I just prefer simple search like the classic vim way, then I use / which maps to evil-ex-search-forward from evil mode 2.

It behaves exactly like what you do with / in vim normal mode.

search in directories

rg

So far ripgrep(rg) 3 seems to be the fatest search tool around and many Emacs packages use it as backend.

By default rg respects .gitignore file but if you want it to search everything, you can use --no-ignore-vcs switch.

Sometimes it finds things from the file I don't want, to prevent that, add a file with name .ignore at the root of git repo as described here 4:

/TAGS
*.min.js*
/Build/Output/
/ThirdParty/

counsel-rg

My favorite Emacs package for searching is counsel-rg 5 and I bind it to C-/. It uses rg as backend.

counsel-rg by default looks for a directory with .git and starts a search from there.

To limit the scope to current directory and its sub directories, not where .git is, use prefix argument before running counsel-rg then select which directory you want to run rg on.

deadgrep

deadgrep 6 is another package which uses rg as backend for searching.

It has many features and allow filtering to be done more easier than counsel-rg.

One notable feature is search on remote host:

If you're editing a remote file with Tramp, deadgrep will search the remote machine. This requires rg to be installed on that machine.

replace in multiple files

For this purpose, this great blog post 7 describes it in detail. It use counsel-ag but same thing works for counsel-rg which is the one I use.

In short, workflow is something like this:

  • C-/ (counsel-rg)

  • type search pattern

  • C-c C-o (ivy-occur) which saves result into a buffer

  • C-x C-q (ivy-wgrep-change-to-wgrep-mode) in ivy-occur buffer

  • :%s/from/to/g to do the replace

  • C-c C-c (wgrep-finish-edit) save the changes

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