The pickaxe is one of Git's most powerful detective tools. It searches diffs across history.
git log -S "calculateTotal" — commits where the number of occurrences of that exact string changed (i.e., someone added or deleted it). Strict literal match.
git log -G "calculate.*Total" — commits where any matching line was modified. Regex. Useful for "find when this function signature changed."
Combine with -p to see the diffs inline:
git log -p -S "deprecated_api"
Pickaxe is the answer to "when was this code introduced?" and "why was this deleted?" — far faster than reading log graphs.