git hook to run a command after `git pull` if a specified file was changed.In this example it's used to run `npm install` if package.json changed and `bower install` if `bower.json` changed.Run `chmod +x post-merge` to make it executable then put it into `.git/hooks/`.

post-merge

#!/usr/bin/env bash
# MIT © Sindre Sorhus - sindresorhus.com

# git hook to run a command after `git pull` if a specified file was changed
# Run `chmod +x post-merge` to make it executable then put it into `.git/hooks/`.

changed_files="$(git diff-tree -r --name-only --no-commit-id ORIG_HEAD HEAD)"

check_run() {
	echo "$changed_files" | grep --quiet "$1" && eval "$2"
}

# Example usage
# In this example it's used to run `npm install` if package.json changed
check_run package.json "npm install"

It works like a charm but I had to fork it https://gist.github.com/GianlucaGuarini/8001627

curl -O https://gist.githubusercontent.com/sindresorhus/7996717/raw/4ec63bc6f8c0f1e227faeb78eddc01a788ef0595/post-merge && chmod +x post-merge && mv post-merge .git/hooks/

How can we share a git hook with the team ?

Auto response: http://stackoverflow.com/questions/3462955/putting-git-hooks-into-repository/3464399#3464399

Failed to run in windows, fix it by add a ! sign , #!/usr/bin/env bash

This hook doesn't work if you run pull with --rebase option. Do you know how to fix it? Thx!

I forked this to work with changes to .scss and .sass file changes. https://gist.github.com/danielcgold/6de270807fc01c793c9a

It seems like HEAD@{1} should be used instead of ORIG_HEAD. Forked here: https://gist.github.com/mariusGundersen/8a4383f74a46ababc1de

@robertcasanova take a look at .git/hooks/pre-rebase.sample and see if you can deduct how to do a post-rebase hook.

@MoOx (and anyone interested): If you're using npm : https://github.com/gtramontina/ghooks

@sindresorhus this is awesome! thank you!

Does post-merge run when there are conflicts during pull?

@Satys.

No, it won't run. "This hook cannot affect the outcome of git merge and is not executed, if the merge failed due to conflicts."

❤️

I would add these checks too:

# Updating git submodules
check_run .gitmodules "git submodule init && git submodule update"

# Installing composer dependencies
check_run composer.json "composer install"

# For those who use gulp
check_run web/assets "gulp --production"

@robertcasanova

This hook doesn't work if you run pull with --rebase option. Do you know how to fix it? Thx!

+1 , same problem. Have you found out the solution?

@aaronroberson

take a look at .git/hooks/pre-rebase.sample and see if you can deduct how to do a post-rebase hook.

I've tried to write a post-rebase hook but it didn't work ...

First line missing a !; should be #!/usr/bin/env bash

post-rewrite works for me. As side effect it is also executed on amend.

http://stackoverflow.com/questions/21307744/git-post-rebase-hook

Awesome! Thanks! It works like a charm.

For package managers that use a lock file, eg. Composer, it would make sense to check if the lock file changed rather than the requirements file, right? In other words:

# Installing composer dependencies
check_run composer.lock "composer install"

Thank you so much, it works like a charm although, I did a few changes on my fork.
https://gist.github.com/betorobson/23e5914b51e844bac5eaa6032d6f3f88

On my machine it is running npm install whether package.json is changed or not.

The way I am reproducing is by creating a new branch at the current commit and then checking it out. Therefore the files should be identical between the two branches.

Anyone have any ideas?

cross-posted with stackoverflow: http://stackoverflow.com/questions/43876375/optional-githook-behaving-as-non-optional

For cases where you are pushing to a bare repo and want to use this on a post-receive hook, instead of the line

changed_files="$(git diff-tree -r --name-only --no-commit-id ORIG_HEAD HEAD)"

one should use

changed_files="$(git diff --name-only HEAD^ HEAD)"

Thank you for an extremely useful snippet!

This only deals with changed files right. Suppose I want to check any new files are generated when taking pull, how this solution works?

thanks for the wonderful solution
extended the script - added the option for conditionally execute the command according to git configuration
https://gist.github.com/oriy/e8b58a6a471d371129b1d0b430510375

@sindresorhus Thanks for the wonderful solution.
I would like to clarify that Is it possible to check and run npm install only if the change is in npm dependency ?
I think that will save some more time.

@robertcasanova

This hook doesn't work if you run pull with --rebase option. Do you know how to fix it? Thx!

+1 , same problem. Have you found out the solution?

@aaronroberson

take a look at .git/hooks/pre-rebase.sample and see if you can deduct how to do a post-rebase hook.

I've tried to write a post-rebase hook but it didn't work ...

post-rebase is not a valid git-hook

You have to implement a post-rewrite hook and check the first argument to be "rebase" (could be "amend" too as @belveryin already tasted).
See https://git-scm.com/docs/githooks#_post_rewrite

How do you run npm install if one of two matching criteria is found? e.g. I want to run npm install if one of two files is modified, but don't want to run npm install twice.

You should be able to run it as
check_run "file1\|file2" "npm install"

Probably, I also need to add '-e' parameter to the 'grep' function

Thanks!

there is this too https://github.com/jonathantneal/post-npm-install

is there any way to show message like this, before & after hooks execution for npm i?
checking for dependency update...

if there is any update going to happen
installing dependency..

if there is no changes to dependency
no new dependency!

This script works like a charm. Thanks for sharing.
Can someone please let me know what is happening inside the script? What does this script arguments mean?