Python script to backup all your brew files and an example of the output.

brew_list_backup.py

class Command(object):
    """
    Run a command and capture it's output string, error string and exit status
    Source: http://stackoverflow.com/a/13848259/354247
    """
    def __init__(self, command):
        self.command = command
    def run(self, shell=True):
        import subprocess as sp
        process = sp.Popen(self.command, shell = shell, stdout = sp.PIPE, stderr = sp.PIPE)
        self.pid = process.pid
        self.output, self.error = process.communicate()
        self.failed = process.returncode
        return self
    @property
    def returncode(self):
        return self.failed

homebrew_packages = Command('brew list').run().output.split()
cask_packages = Command('brew cask list').run().output.split()

brew = ''.join(['install %s \n' % item for item in homebrew_packages])
cask = ''.join(['cask install %s \n' % item for item in cask_packages])

file_output = """
cleanup
update
upgrade

# Install the normal packages
%s

# Now install our cask stuff
install caskroom/cask/brew-cask

%s

cleanup""" % (brew, cask)

print file_output

Brewfile

cleanup
update
upgrade

# Install the normal packages
install a52dec 
install ack 
install aften 
install android-ndk 
install android-sdk 
install ant 
install astyle 
install atk 
install autoconf 
install autojump 
install automake 
install bash-completion 
install bison 
install boost 
install brew-cask 
install cairo 
install cassandra 
install cmake 
install coreutils 
install cscope 
install curl 
install dex2jar 
install dos2unix 
install doxygen 
install ec2-api-tools 
install faac 
install faad2 
install fcrackzip 
install fontconfig 
install freetype 
install gdbm 
install gdk-pixbuf 
install gettext 
install gist 
install git 
install git-extras 
install glib 
install gnupg 
install gobject-introspection 
install gradle 
install grc 
install gtk+ 
install gtksourceview 
install harfbuzz 
install highlight 
install icu4c 
install imagemagick 
install intltool 
install jasper 
install jpeg 
install jq 
install lame 
install libdca 
install libevent 
install libffi 
install libgpg-error 
install libksba 
install libmemcached 
install libogg 
install libpng 
install librsync 
install libtiff 
install libtool 
install libvorbis 
install libvpx 
install libxml2 
install libxslt 
install libyaml 
install little-cms 
install lua 
install macvim 
install mad 
install makedepend 
install maven 
install meld 
install memcached 
install mercurial 
install multimarkdown 
install mysql 
install node 
install opencore-amr 
install openssl 
install ossp-uuid 
install pango 
install pcre 
install phantomjs 
install pixman 
install pkg-config 
install pngquant 
install popt 
install postgresql 
install py2cairo 
install pygobject 
install pygtk 
install pygtksourceview 
install python 
install python3 
install qt 
install rarian 
install rbenv 
install readline 
install reattach-to-user-namespace 
install ruby-build 
install spark 
install spdylay 
install sqlite 
install the_silver_searcher 
install vim 
install watchman 
install wget 
install x264 
install xvid 
install xz 
install yasm 


# Now install our cask stuff
install caskroom/cask/brew-cask

cask install alfred 
cask install android-file-transfer 
cask install appcleaner 
cask install atom 
cask install caffeine 
cask install ccleaner 
cask install charles 
cask install cloud 
cask install dash 
cask install diffmerge 
cask install dropbox 
cask install evernote 
cask install filezilla 
cask install firefox 
cask install flux 
cask install genymotion 
cask install google-chrome 
cask install handbrake 
cask install intellij-idea-ce 
cask install iterm2 
cask install kindle 
cask install macvim 
cask install onepassword 
cask install pycharm 
cask install rdio 
cask install skype 
cask install sopcast 
cask install spectacle 
cask install spotify 
cask install sublime-text3 
cask install textmate 
cask install the-unarchiver 
cask install utorrent 
cask install vagrant 
cask install virtualbox 
cask install vlc 


cleanup

Depends on OSX python, but also installs python with brew.

Just in case, but I don't think I'll ever want to do this...

# Specify your defaults in this environment variable
export HOMEBREW_CASK_OPTS="--appdir=/Applications --caskroom=/etc/Caskroom"

Now that this is deprecated you might want to have a look at https://github.com/Homebrew/homebrew-brewdler