(or emacs irrelevant)

Using exclusion patterns when grepping

05 Mar 2018

Git

I like Git. A lot. After years of use it has really grown on me. It's (mostly) fast, (often) reliable, and (always) distributed. For me, all properties are important, but being able to do git init to start a new project in seconds is the best feature.

When it comes to working with Git day-to-day, a nice GUI can really make a difference. In Emacs world, of course it's Magit. Outside of Emacs (brr), git-cola looks to be the most promising one. If you're aware of something better, please share - I'm keeping a list of suggestions for my non-Emacs using colleagues.

Ivy integration for Git

The main two commands in ivy that I use for Git are:

  • counsel-git: select a file tracked by Git
  • counsel-rg: grep for a line in all files tracked by Git, using ripgrep as the backend.

There are many alternatives to counsel-rg that use a different backend: counsel-git-grep, counsel-ag, counsel-ack, counsel-pt. But counsel-rg is the fastest, especially when I have to deal with Git repositories that are 2Gb in size (short explanation: it's a Perforce repo with a bunch of binaries, because why not; and I'm using git-p4 to interact with it).

Using .ignore with ripgrep

Adding an .ignore file to the root of your project can really speed up your searches. In my sample project, I went from 10k files to less than 500 files.

Example content:

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

As you can see, both file patterns and directories are supported. One other nifty thing that I discovered only recently is that you can use ripgrep as the backed for counsel-git in addition to counsel-rg. Which means the same .ignore file is used for both commands. Here's the setting:

(setq counsel-git-cmd "rg --files")

And here's my setting for counsel-rg:

(setq counsel-rg-base-command
      "rg -i -M 120 --no-heading --line-number --color never %s .")

The main difference in comparison to the default counsel-rg-base-command is -M 120 which means: truncate all lines that are longer than 120 characters. This is really helpful when Emacs is accepting input from ripgrep: a megabyte long line of minified JS is not only useless since you can't see it whole, but it will also likely hang Emacs for a while.

Outro

I hope you found these bits of info useful. Happy hacking!