Git post-receive hook for automatically deploying a new version of my sites

post-receieve

#!/bin/bash
# CHANGE THIS TO MATCH YOUR PROJECT
root_dir=/var/www/example.com;

while read oldrev newrev refname
do
    branch=$(git rev-parse --symbolic --abbrev-ref $refname);
    branch_dir=$root_dir/$branch/$newrev;

    echo "[CI] Commit recieved on branch $branch";
    echo "[CI] CREATE DIR " $branch_dir && mkdir $branch_dir;
    git --work-tree=$branch_dir checkout -f $branch;

    # now move the checked out code into a versioned folder
    version=$(node /var/git/version.js $branch_dir/package.json);
    version_dir=$root_dir/$branch/$version

    echo "[CI] REMOVE (if exists) " $version_dir && rm -rf $version_dir
    echo "[CI] Move " $branch_dir " to " $version_dir && mv $branch_dir $version_dir;

    # now run the grunt script there
    echo "[CI] npm install";
    cd $version_dir && npm install;

    echo "[CI] grunt";
    grunt --base=$version_dir --gruntfile $version_dir/Gruntfile.js $branch;

    # link in the new version
    echo "[CI] Linking version $version as CURRENT";
    unlink $root_dir/$branch/current;
    ln -s $version_dir $root_dir/$branch/current;

    # Stop the old and start the new
    echo "[CI] Stopping old version.";
    forever stop $root_dir/$branch/current/app.js;

    echo "[CI] Starting new version.";
    forever start $root_dir/$branch/current/app.js;

    echo "[CI] Success";
done