Using Git, how could I search for a string across all branches?

Using Git, how could I search within all files in all local branches for a given string?

GitHub specific: is it possible to perform the above search across all GitHub branches? (There are several remote branches on my remote GitHub repository that ideally I wouldn't have to bring down for this search...)

You can do this on a Git repository:

git grep "string/regexp" $(git rev-list --all)

GitHub advanced search has code search capability:

The code search will look through all of the code publicly hosted on GitHub. You can also filter by:

• the language: language:
• the repository name (including the username): repo:
• the file path: path:

If you use @manojlds Git grep command and get an error:

-bash: /usr/bin/git: Argument list too long" 

then you should use xargs:

git rev-list --all | xargs git grep "string/regexp"

Also see How to grep (search) committed code in the Git history

In many cases git rev-list --all can return a huge number of commits, taking forever to scan. If you, instead of searching through every commit on every branch in your repository history, just want to search all branch tips, you can replace it with git show-ref -s --heads. So in total:

git grep "string" `git show-ref -s --heads`

or:

git show-ref -s --heads | xargs git grep "string"

Tip: You can write output in file to view in an editor:

nano ~/history.txt
git show-ref -s --heads | xargs git grep "search string here" >> ~/history.txt

There are a few issues with the solutions listed here (even accepted).

You do not need to list all the hashes as you'll get duplicates. Also, it takes more time.

It builds on this where you can search a string "test -f /" on multiple branches master and dev as

git grep "test -f /" master dev

which is same as

printf "master\ndev" | xargs git grep "test -f /"

So here goes.

This finds the hashes for the tip of all local branches and searches only in those commits:

git branch -v --no-abbrev | awk -F' *' '{print $3}' | xargs git grep "string/regexp"

If you need to search in remote branches too then add -a:

git branch -a -v --no-abbrev | awk -F' *' '{print $3}' | xargs git grep "string/regexp"

Further:

# Search in local branches
git branch | cut -c3- | xargs git grep "string"

# Search in remote branches
git branch -r | cut -c3- | xargs git grep "string"

# Search in all (local and remote) branches
git branch -a | cut -c3- | cut -d' ' -f 1 | xargs git grep "string"

# Search in branches, and tags
git show-ref | grep -v "refs/stash" | cut -d' ' -f2 | xargs git grep "string"