Git post-commit hook for modifying .md files to work with gh-pages and just copy other files, like .png, .css and so on.

git-hooks.pl

#!/usr/bin/env perl

use strict;
use warnings;
use v5.14;
use Git::Hooks;
use File::Slurp qw(read_file write_file);

my $layout_preffix=<<EOT;
---
layout: index
---
EOT

POST_COMMIT {
  my ($git) = @_;
  my $branch =  $git->command(qw/rev-parse --abbrev-ref HEAD/);
  if ( $branch =~ /master/ ) {
    my $changed = $git->command(qw/show --name-status/);
    my @changed_files = ($changed =~ /\s\w\s+(\S+)/g);
    my @mds = grep ( /\.md/, @changed_files );
    my @copies = grep( /(\.png|\.jpg)/, @changed_files );
    #Now change branch and process
    #Inspired by http://stackoverflow.com/questions/15214762/how-can-i-sync-documentation-with-github-pages
    $git->command(qw/checkout gh-pages/);
    for my $f ( @mds ) {
      $git->command( 'checkout', 'master', '--', $f );
      my $file_content = read_file( $f );
      $file_content =~ s/\.md\)/\)/g; # Change links
      $file_content = $layout_preffix.$file_content;
      if ( $f ne 'README.md' ) {
	write_file($f, $file_content);
	$git->command('add', $f );
      } else {
	write_file('index.md', $file_content );
	$git->command('add', 'index.md' );
	unlink('README.md');
      }
      say "Processing $f";
    }
    for my $c (@copies ) {
      $git->command( 'checkout', 'master', '--', $c );
      $git->command('add', $c );
      say "Copying $c";
    }
    $git->command('commit','-a', '-m', "Sync ".
		  join( " ", @mds)." and ". 
		  join( " ", @copies)." from master to gh-pages");
    $git->command(qw/checkout master/); #back to original
  }
};

run_hook($0, @ARGV);

=head1 NAME

git-hooks.pl - post-commit hooks to sync markdown pages with GitHub pages

=head2 SYNOPSIS

First you need to install C<Git::Hooks> and C<File::Slurp>. I use say,
so you will need perl > 5.10. Besides, you need to locate Git.pm and
copy it where the file can find it. That depends on the OS and perl
installation you're using (I use perlbrew), In my case it was:

  bash% cp /usr/share/perl5/Git.pm ~/perl5/perlbrew/perls/perl-5.16.1/lib/site_perl/5.16.1/

Then copy git-hooks.pl to .git/hooks, make it runnable (chmod +x
    git-hooks) and then

  bash% ln -s git-hooks.pl post-commit

Any trouble, just check the L<Git::Hooks> manual.

=head1 LICENSE

This is released under the Artistic 
License. See L<perlartistic>.

=head2 AUTHOR

JJ Merelo, L<jj@merelo.net>