Script to install/update mono for mac from canonical official pkg installer on download.mono-project.com

install-mono.sh

#!/bin/sh

current_userid=$(id -u)
if [ $current_userid -ne 0 ]; then
    echo "$(basename "$0") requires superuser privileges to run" >&2
    exit 1
fi

INSTALLED_VERSION=$(mono --version 2> /dev/null | grep -o -E 'version [0-9\.]+'| grep -o -E [0-9\.]+)
STABLE_VERSION=$(curl -s https://www.mono-project.com/download/stable/ | grep -o -E 'Stable \(.+\)' | grep -E -o '[0-9\.]+')

do_install() {
    MAJOR_VERSION=$(echo $STABLE_VERSION | grep -o -E '([0-9\]+\.){,3}' | cut -d'.' -f1-3)
    URL="https://download.mono-project.com/archive/${MAJOR_VERSION}/macos-10-universal/"
    FILE="MonoFramework-MDK-${STABLE_VERSION}.macos10.xamarin.universal.pkg"

    echo "Downloading mono ${STABLE_VERSION} pkg installer."
    curl "${URL}${FILE}" > "/tmp/${FILE}"
    echo "Installing mono ${STABLE_VERSION}"
    installer -pkg "/tmp/${FILE}" -target /
    rm "/tmp/${FILE}"

    eval $(/usr/libexec/path_helper -s)
}

if [ "$INSTALLED_VERSION" = "$STABLE_VERSION" ]; then
    echo "mono $INSTALLED_VERSION is up to date."
else
    do_install
fi