Create an inventory of installed Homebrew formulae, preserving flags

brew-inventory.sh

#!/usr/bin/env bash

brew list | while read formula; do
    command="brew install $formula" 
    flags="$(brew info $formula | grep -i "built from source .* with:" | cut -f 11- -d' ')"
    echo $command $flags
done

# Usage:
# ./brew-inventory.sh >! brew-formulae.txt

# To install from inventory output i.e. brew-formulae.txt:
# eval "$(cat brew-formulae.txt)"

UPDATE: Just use https://github.com/Homebrew/homebrew-bundle