install specific version formula with homebrew

brew_version.sh

#=============================================================================
#     FileName: brew_version
#         Desc: install specific version formula with homebrew
#           Usage: brew_version <formula> <version> [param1 param2 ...]
#       Author: KuoE0
#        Email: kuoe0.tw@gmail.com
#     HomePage: http://kuoe0.ch/
#=============================================================================
# /usr/bin/env bash

formula=$1
version=$2
# concatenate addition parameters
for ((i=3; i <= $#; ++i)); do
	param=$param' '${!i}
done

# open homebrew directory
cd `brew --prefix`

# list all version avalible
version_list=$(brew versions $formula 2>/dev/null)
# regex for remove version number
re_version="s/[[:digit:]]+(\.[[:digit:]]+)*[[:space:]]*//"

# get the command for specific formula
checkout_cmd=$(echo "$version_list" | grep $version | sed -E $re_version)
echo $checkout_cmd
# git checkout to specific version
`$checkout_cmd`

# unlink formula
echo "brew unlink $formula"
brew unlink $formula

# install specific formula and use addition parameters
echo "brew install $formula $param"
brew install $formula

# switch to the specific formula
echo "brew switch $formula $version"
brew switch $formula $version

# reset homebrew repo
reset_cmd=$(echo "$version_list" | sed -n '1p' | sed -E $re_version)
echo "$reset_cmd"
`$reset_cmd`