A post-receive hook that runs a script if changes were pushed to a specific branch. (Hook scripts are in the hooks/ directory of a Git repository, and must be executable.)

post-receive

#!/bin/sh

# 1. Create symlinks to the real upgrade scripts for each branch, for example:
#     ./upgrade-beta.sh  # will only be called when "beta" branch is updated
#     ./upgrade-prod.sh  # will only be called when "prod" branch is updated
#
# 2. Put these symlinks in the repository root, NOT in the hooks/ directory

# the post-receive hook receives parameters on stdin
while read oldrev newrev refname
do
    branch=$(git rev-parse --symbolic --abbrev-ref $refname)
    upgrade_sh=./upgrade-$branch.sh
    if test -e $upgrade_sh; then
        upgrade_sh=$(readlink $upgrade_sh || echo $upgrade_sh)
        echo calling upgrade script: $upgrade_sh
        $upgrade_sh
    else
        echo NOT calling non-existent upgrade script: $upgrade_sh
    fi
done