Script to activate Ruby Gem Bundler environment in current shell session.

bundle-activate.sh

#!/bin/sh
#
# This script activates a Gem Bundler environment in current shell
# session. This lets you type commands without `bundle exec` all the
# time, even if you leave the project's directory, and without complex
# magic that runs with every command.
#
# Usage: save this file somewhere. Use following command to activate
# current directory's bundle in current shell session:
#
#     eval `/path/to/bundle-activate`
#
# For convenience you may add alias to your shell's initialization
# file (e.g. ~/.profile):
#
#     alias ba='eval `path/to/bundle-activate`'
#

set -e

old=`mktemp env.unbundled.XXXXX`
new=`mktemp env.bundled.XXXXX`
out=`mktemp env.changed.XXXXX`

env > $old
bundle exec env > $new

fgrep -v -f $old $new \
    | grep -v '^_=' \
    | sed "s/'/'\\\\''/g; s/^/'/; s/$/'/" \
    > $out

prj="`grep '^BUNDLE_GEMFILE=' $new | cut -d= -f2-`"
prj="`dirname $prj`"
prj="`basename $prj`"

echo "PS1=\"(bundle@$prj)\$PS1\"" >> $out

tr \\n \\0 < $out | xargs -0 echo export

rm $old $new $out