How to grep Git commit diffs or contents for a certain word

Question

In a Git code repository I want to list all commits that contain a certain word. I tried this

git log -p | grep --context=4 "word"

but it does not necessarily give me back the filename (unless it's less that five lines away from the word I searched for. I also tried

git grep "word"

but it gives me only present files and not the history.

How do I search the entire history so I can follow changes on a particular word? I intend to search my codebase for occurrences of word to track down changes (search in files history).

Answer 1

If you want to find all commits where the commit message contains a given word, use

$ git log --grep=word

If you want to find all commits where "word" was added or removed in the file contents (to be more exact: where the number of occurrences of "word" changed), i.e., search the commit contents, use a so-called 'pickaxe' search with

$ git log -Sword

In modern Git there is also

$ git log -Gword

to look for differences whose added or removed line matches "word" (also commit contents).

Note that -G by default accepts a regex, while -S accepts a string, but it can be modified to accept regexes using the --pickaxe-regex.

To illustrate the difference between -S<regex> --pickaxe-regex and -G<regex>, consider a commit with the following diff in the same file:

+    return !regexec(regexp, two->ptr, 1, &regmatch, 0);
...
-    hit = !regexec(regexp, mf2.ptr, 1, &regmatch, 0);

While git log -G"regexec\(regexp" will show this commit, git log -S"regexec\(regexp" --pickaxe-regex will not (because the number of occurrences of that string did not change).

---

With Git 2.25.1 (Feb. 2020), the documentation is clarified around those regexes.

See commit 9299f84 (06 Feb 2020) by Martin Ågren (``). ^{(Merged by Junio C Hamano -- gitster -- in commit 0d11410, 12 Feb 2020)}

diff-options.txt: avoid "regex" overload in the example \

^{Reported-by: Adam Dinwoodie
Signed-off-by: Martin Ågren
Reviewed-by: Taylor Blau}

When we exemplify the difference between -G and -S (using --pickaxe-regex), we do so using an example diff and git diff invocation involving "regexec", "regexp", "regmatch", etc.

The example is correct, but we can make it easier to untangle by avoiding writing "regex.*" unless it's really needed to make our point.

Use some made-up, non-regexy words instead.

The git diff documentation now includes:

To illustrate the difference between -S<regex> --pickaxe-regex and -G<regex>, consider a commit with the following diff in the same file:

+    return frotz(nitfol, two->ptr, 1, 0);

...
-    hit = frotz(nitfol, mf2.ptr, 1, 0);

While git log -G"frotz\(nitfol" will show this commit, git log -S"frotz\(nitfol" --pickaxe-regex will not (because the number of occurrences of that string did not change).

Answer 2

git log's pickaxe will find commits with changes including "word" with git log -Sword

Answer 3

After a lot of experimentation, I can recommend the following, which shows commits that introduce or remove lines containing a given regexp, and displays the text changes in each, with colours showing words added and removed.

git log --pickaxe-regex -p --color-words -S "<regexp to search for>"

Takes a while to run though... ;-)

Answer 4

One more way/syntax to do it is: git log -S "word"
Like this you can search for example git log -S "with whitespaces and stuff @/#ü !"

Answer 5

You can try the following command:

git log --patch --color=always | less +/searching_string

or using grep in the following way:

git rev-list --all | GIT_PAGER=cat xargs git grep 'search_string'

Run this command in the parent directory where you would like to search.

Answer 6

vim-fugitive is versatile for that kind of examining in Vim.

Use :Ggrep to do that. For more information you can install vim-fugitive and look up the turorial by :help Grep. And this episode: exploring-the-history-of-a-git-repository will guide you to do all that.

Answer 7

To use a Boolean connector on a regular expression:

git log --grep '[0-9]*\|[a-z]*'

This regular expression searches for the regular expression [0-9]* or [a-z]* in commit messages.

Answer 8

If you want search for sensitive data in order to remove it from your Git history (which is the reason why I landed here), there are tools for that. GitHub as a dedicated help page for that issue.

Here is the gist of the article:

The BFG Repo-Cleaner is a faster, simpler alternative to git filter-branch for removing unwanted data. For example, to remove your file with sensitive data and leave your latest commit untouched), run:

bfg --delete-files YOUR-FILE-WITH-SENSITIVE-DATA

To replace all text listed in passwords.txt wherever it can be found in your repository's history, run:

bfg --replace-text passwords.txt

See the BFG Repo-Cleaner's documentation for full usage and download instructions.