git pickaxe

Sometimes you want to find out when a specific term was added or removed that might not be directly mentioned in a commit message. This is where git log -S <pattern>, apparently also referred to as "git pickaxe" comes in useful.

$ git log -S ZLIB_BUF_MAX --oneline
e01503b zlib: allow feeding more than 4GB in one go
ef49a7a zlib: zlib can only process 4GB at a time

via Git - Searching, example also stolen directly from there