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"
}

check_run README.md "echo 'README.md changed!';git diff ORIG_HEAD -- README.md"
check_run .env.example "echo '.env.example changed!';git diff ORIG_HEAD -- .env.example"
check_run package.json "echo 'package.json changed! Running npm install.';npm install"

Example showing the specific checks I used for one of my repositories