brew-merge.sh

#!/bin/bash
# @link https://gist.github.com/lavoiesl/eac60efde00c1df49c73

function usage() {
    echo "Homebrew manager"
    echo "Use dump-merge to save a list of installed brews to Dropbox"
    echo "Use install to install missing brews"
    echo "Usage: ${0} [--cask] [--directory directory] [--hostname hostname] dump|merge|dump-merge|diff|install" >&2
    exit 255
}

cask=""
extension="list"
directory="${HOME}/Dropbox/brew-merge"
hostname=""
cmd=""
autoconfirm=""

while [ $# -gt 0 ]
do
    case "${1}" in
        --cask ) cask="cask"; extension="cask.list" ;;
        --directory ) if [ -d "${2}" ]; then directory="${2}"; shift; else echo "--directory argument must be a directory" >&2; exit 1; fi ;;
        --hostname ) if [ -n "${2}" ]; then hostname="${2}"; shift; else echo "--hostname argument must not be empty" >&2; exit 1; fi ;;
        -y ) autoconfirm="-y" ;;
        -* ) echo "$0: error - unrecognized option $1" >&2; exit 1;;
        * ) cmd="${1}" ;;
    esac

    shift
done

function ensure_directory() {
    local directory="${1}"

    if [ ! -d "$(dirname "${directory}")" ]; then
        echo "$(dirname "${directory}") does not exist" >&2
        exit 1
    fi

    [ -d "${directory}" ] || mkdir "${directory}"
}

function list_installed() {
    if [[ "${cask}" == "cask" ]]; then
        brew cask list -1
    else
        brew leaves -1
    fi
}

function diff_installed() {
    local hostname="${1}"

    if [ ! -f "${directory}/${hostname}.${extension}" ]; then
        echo "You must run '${0} dump' first." >&2;
        exit 255;
    fi

    list_installed | diff "${directory}/${hostname}.${extension}" - | grep -E '^(?:<|>) '
}

function prompt_value() {
    local prompt="$1 "
    local default="$2"

    [[ -n "$default" ]] && prompt="$prompt($default) "

    read -p "$prompt" reply

    [[ -z "$reply" ]] && reply="$default"

    if [[ -z "$reply" ]]; then
        prompt_value "$prompt" "$default"
        exit
    fi

    echo "$reply"
}

function confirm() {
    local prompt="$1"

    if [[ -n "$autoconfirm" ]]; then
        echo "$prompt (Y/n) y"
    else
        read -p "$prompt (Y/n) " reply
    fi

    [[ $reply != "n" ]]

    return $?
}


case "${cmd}" in
    dump )
        hostname="${hostname:-$(hostname)}"
        ensure_directory "${directory}"

        count=$(list_installed | tee "${directory}/${hostname}.${extension}" | wc -l)
        echo Saved $count formulas to "${directory}/${hostname}.${extension}"
        ;;

    merge )
        hostname="${hostname:-$(hostname)}"
        ensure_directory "${directory}"
        if [ ! -f "${directory}/${hostname}.${extension}" ]; then echo "You must run '${0} dump' first." >&2; exit 255; fi

        [ -f "${directory}/common.${extension}" ] || touch "${directory}/common.${extension}"
        count=$(cat "${directory}/common.${extension}" "${directory}/${hostname}.${extension}" | sort | uniq | tee "${directory}/common.${extension}" | wc -l)
        echo Saved $count formulas to "${directory}/common.${extension}"
        ;;

    dump-merge )
        hostname="${hostname:-$(hostname)}"

        $0 --directory "${directory}" --hostname "${hostname}" dump
        $0 --directory "${directory}" --hostname "${hostname}" merge

        if brew cask 2>&1 >/dev/null; then
            $0 --cask --directory "${directory}" --hostname "${hostname}" dump
            $0 --cask --directory "${directory}" --hostname "${hostname}" merge
        fi
        ;;

    diff )
        hostname="${hostname:-common}"
        diff_installed "${hostname}" | sort
        ;;

    install )
        hostname="${hostname:-common}"
        diff="$(diff_installed "${hostname}")"
        missing=$(echo "${diff}" | grep "^< " | sed 's/^< //')
        extra=$(echo "${diff}" | grep "^> " | sed 's/^> //')

        if [[ -n "${extra}" ]]; then
            echo "You have brews that are not yet saved:"
            echo "${extra}"
            confirm "Continue?" || exit 0
        fi

        if [[ -n "${missing}" ]]; then
            echo "Installing missing brews:"
            echo "${missing}" | xargs echo
            confirm "Continue?" || exit 0
            echo "${missing}" | xargs brew $cask install
        else
            echo "Already up-to-date!"
        fi
        ;;

    *) usage
        ;;
esac