ericatkinson · May 19, 2012 15:31 · Sep 18, 2010
diff --git a/post-receive.rb b/post-receive.rb
@@ -0,0 +1,41 @@
+#!/usr/bin/env ruby
+
+# Aside from removing Ruby on Rails specific code this is taken verbatim from
+# mislav's git-deploy (http://github.com/mislav/git-deploy) and it's awesome
+#  - Ryan Florence (http://ryanflorence.com)
+#
+# Install this hook to a remote repository with a working tree, when you push
+# to it, this hook will reset the head so the files are updated
+
+if ENV['GIT_DIR'] == '.'
+  # this means the script has been called as a hook, not manually.
+  # get the proper GIT_DIR so we can descend into the working copy dir;
+  # if we don't then `git reset --hard` doesn't affect the working tree.
+  Dir.chdir('..')
+  ENV['GIT_DIR'] = '.git'
+end
+
+cmd = %(bash -c "[ -f /etc/profile ] && source /etc/profile; echo $PATH")
+envpath = IO.popen(cmd, 'r') { |io| io.read.chomp }
+ENV['PATH'] = envpath
+
+# find out the current branch
+head = `git symbolic-ref HEAD`.chomp
+# abort if we're on a detached head
+exit unless $?.success?
+
+oldrev = newrev = nil
+null_ref = '0' * 40
+
+# read the STDIN to detect if this push changed the current branch
+while newrev.nil? and gets
+  # each line of input is in form of "<oldrev> <newrev> <refname>"
+  revs = $_.split
+  oldrev, newrev = revs if head == revs.pop
+end
+
+# abort if there's no update, or in case the branch is deleted
+exit if newrev.nil? or newrev == null_ref
+
+# update the working copy
+`umask 002 && git reset --hard`