Sync Homebrew installations between Macs via Dropbox

brew-sync.sh

#!/bin/bash

# Sync Homebrew installations between Macs via Dropbox
#

BREW="/usr/local/bin/brew"
DROPBOX_FOLDER=~/dropbox/.configs/Homebrew
BREWFILE="${DROPBOX_FOLDER}/Brewfile"
BREWFILE_TMP="/tmp/Brewfile"

# first dump local Homebrew bundle
echo "Bundling local Homebrew dependencies ..."
rm -f ${BREWFILE_TMP}
${BREW} bundle dump --file=${BREWFILE_TMP}

# then combine it with Brewfile in Dropbox
if [ -f "${BREWFILE}" ]
then
	echo "Combining with Brewfile from Dropbox ..."
	cat ${BREWFILE} >> ${BREWFILE_TMP}
else
	echo
	read -p "No Brewfile found in Dropbox ... Continue anyway? " -n 1 -r
	echo
	if [[ ! ${REPLY} =~ ^[Yy]$ ]]
	then
	    [[ "$0" = "${BASH_SOURCE}" ]] && exit 1 || return 1
	fi
fi

# make the Brewfile unique and sync into Dropbox
echo "Syncing to Dropbox ..."
mkdir -p "${DROPBOX_FOLDER}"
cat ${BREWFILE_TMP} | sort | uniq > ${BREWFILE}

echo "Checking dependencies ..."
if ${BREW} bundle check --quiet --file=${BREWFILE}
then
	echo "Done!"
else
	echo "Updating dependencies ... "
	${BREW} bundle install --quiet --file=${BREWFILE}
	echo "Done!"
fi