[brcrth]

And if your editor is Emacs, you can use this: https://github.com/Wilfred/ag.el

[lepht]

Obligatory vim equivalent: https://github.com/rking/ag.vim

[unwind]

As long as we're plugging: I realize nobody here would ever use Geany, but my Gitbrowser plug-in for that teeny-tiny editor/IDE has a keyboard shortcut to do git grep, and make the results clickable. See https://github.com/unwind/gitbrowser#greping-a-repository.