install_system_packages_macos

#!/bin/sh
#
# Install interesting packages for OS X.
#
# This assumes that the current user is the user used to install
# packages and has the proper administrator privileges.

set -e
set -u

# package manager
pm=
pm_check=
pm_update=
pm_upgrade=
pm_install=
pm_cleanup=
pm_autoremove=

# check if Homebrew is installed
if [ -z "$(command -v brew 2> /dev/null)" ]; then
    printf "warning: Homewbrew (brew) not found.\n" 1>&2
else
    pm="brew"
    pm_check="${pm} doctor"
    pm_update="${pm} update"
    pm_upgrade="${pm} upgrade"
    pm_install="${pm} bundle"
    pm_autoremove="${pm} autoremove"
    pm_cleanup="${pm} cleanup -s"
fi

# check if package manager is installed
if [ -z "${pm}" ]; then
    prinrf "error: Package manager not found.\n"
    exit 1
fi

# update and check packages
${pm_update}
if ! ${pm_check} ; then
    printf "warning: Package manager check failed, continue anyway (y/n)?: "
    read -r yn
    if [ "${yn}" != "y" ]; then
	exit 1
    fi
fi
${pm_update}

# upgrade existing packages
${pm_upgrade}

# install packages
${pm} bundle

# cleanup
${pm_autoremove}
${pm_cleanup}