How can I grep Git commits 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).

A few things to note:

• -G by default accepts a regex, while -S accepts a string, but it can be modified to accept regexes using the --pickaxe-regex.
• -S finds commits where the number of occurrences of "word" changed, while -G finds commits where "word" appears in the diff.
• This means that -S<regex> --pickaxe-regex and -G<regex> do not do exactly the same thing.

The git diff documentation has a nice explanation of the difference:

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).

This will show the commits containing the search terms, but if you want to see the actual changes in those commits instead you can use --patch:

git log -G"searchTerm" --patch

This can then be piped to grep to isolate the output just to display commit diff lines with that search term. A common use-case is to display diff lines with that search term in commits since and including a given commit - 3b5ab0f2a1 in this example - like so:

git log 3b5ab0f2a1^.. -G"searchTerm" --patch | grep searchTerm

Answer 2

This is useful in combination with BFG (Git filter branch - not to be confused with git-filter-branch) and git-filter-repo. It just gets the file paths so that you can feed them into one of the two tools I just mentioned.

A. Relative, unique, sorted, paths:

# Get all unique filepaths of files matching 'password'
# Source: https://stackoverflow.com/a/69714869/10830091
git rev-list --all | (
    while read revision; do
        git grep -F --files-with-matches 'password' $revision | cat | sed "s/[^:]*://"
    done
) | sort | uniq

B. Unique, sorted, filenames (not paths):

# Get all unique filenames matching 'password'
# Source: https://stackoverflow.com/a/69714869/10830091
git rev-list --all | (
    while read revision; do
        git grep -F --files-with-matches 'password' $revision | cat | sed "s/[^:]*://"
    done
) | xargs basename | sort | uniq

This second command is useful for BFG, because it only accept file names and not repo-relative/system-absolute paths.

There you go. Enjoy using these Bash snippets for as much agony as they caused to me. I hate Bash, so why do I keep using it?

Dissection

Get file names/paths only

Any of the following options mean the same (git-rep documentation):

• -l
• --files-with-matches
• --name-only

Instead of showing every matched line, show only the names of files that contain Blockquote

Is your pattern: A. Regex v.s. B. Fixed String?

As for -F, well, it just means use a fixed string instead a regex for pattern interpretation. A source.

Another useful note that belongs here: You can throw in -i or --ignore-case to be case insensitive.

Get rid of that stupid leading commit hash

sed "s/[^:]*://"

Source.

Get them unique paths!

| sort | uniq

Who wants duplicate paths? Not you, not me! Oh hey look, they are sorted too! Enjoy.

Source: me. I have used this for as long as I can remember. (man sort and man uniq)

What about file names without paths?

xargs basename

You would think | basename would work, but no. It does not accept input standard input, but as command line arguments. Here's an explanation for that. Go figure! basename basically returns the stem filename without its leading path. man basename.

For method A., I want absolute paths not relative.

Sure, just slap a realpath at the end. Like so:

) | sort | uniq | xargs realpath

Of course you have to use xargs because realpath does not use standard input for input. It uses command-line arguments. Just like dirname.

Inspirations

• Check out this awesome alternative answer.
• Search all of Git history for a string
• File names only using Git grep

Answer 3

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.

Answer 4

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 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

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 7

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 8

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

Answer 9

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.