Git Interactive Patching

The git add --patch command interactively add hunks to the index. It effectively runs git add --interactive, but bypasses the initial command menu and directly jumps to the patch subcommand.

If you know that you want to commit after adding a patch, run git commit --patch. This effectively runs git add --patch first, immediately followed by git commit.

You can also interactively reset an index (git reset --patch). This is useful command to know, especially if you've ever painstakingly setup a patch only to press y by mistake and add a hunk that you didn't want, and then had to reset the index and start again. I have several of those t-shirts.

git add --patch

The patch prompt can be intimidating, but everything is easy when you know how.

When you run git add --patch (git add -p for short), you get prompted with the first hunk (if any), and git waits for response to a question:

$ Stage this hunk [y,n,q,a,d,/,s,e,?]?

Do you want to add this hunk to the index? Our options are the comma-delimited list in the square brackets: [y,n,q,a,d,/,s,e,?].

What do they mean? You can press ? (which is one of the options) for help. Git will display something like this:

$ Stage this hunk [y,n,q,a,d,/,s,e,?]?
y - stage this hunk
n - do not stage this hunk
q - quit; do not stage this hunk or any of the remaining ones
a - stage this hunk and all later hunks in the file
d - do not stage this hunk or any of the later hunks in the file
g - select a hunk to go to
/ - search for a hunk matching the given regex
j - leave this hunk undecided, see next undecided hunk
J - leave this hunk undecided, see next hunk
k - leave this hunk undecided, see previous undecided hunk
K - leave this hunk undecided, see previous hunk
s - split the current hunk into smaller hunks
e - manually edit the current hunk
? - print help

The ones you will mostly use are y, n, q, s, and a. If you're new to this command then learn these commands, because this is 80% of the value in using the command. I'll blog about the e option, which can useful in some situations, another day.

To test the command out, use a test git repository. Trying out a new command on a real repository with real changes can make us nervous about using the command. Go create a gitdemo directory somewhere and get familiar with patching.

Making --patch respond to single keystrokes

By default, --patch commands wait for you to press Enter at each prompt i.e. after you've answered the question: Stage this hunk [y,n,q,a,d,/,s,e,?]?. To skip the need to press enter, enable interactive.singlekey:

$ git config --global interactive.singlekey true

On Ubuntu you'll need to install libterm-readkey-perl:

$ sudo apt-get install libterm-readkey-perl

Further reading

• Interactive Staging