detect-os.sh

#!/bin/bash

unameOut=$(uname -a)
case "${unameOut}" in
    *Microsoft*)     OS="WSL";; #must be first since Windows subsystem for linux will have Linux in the name too
    *microsoft*)     OS="WSL2";; #WARNING: My v2 uses ubuntu 20.4 at the moment slightly different name may not always work
    Linux*)          OS="Linux";;
    Darwin*)         OS="Mac";;
    CYGWIN*)         OS="Cygwin";;
    MINGW*)          OS="Windows";;
    *Msys)           OS="Windows";;
    *)               OS="UNKNOWN:${unameOut}"
esac

echo ${OS};

echo "$OSTYPE";

if [[ "$OSTYPE" == "linux-gnu"* ]]; then
    echo "Linux";
elif [[ "$OSTYPE" == "darwin"* ]]; then
    echo "OSX";
elif [[ "$OSTYPE" == "cygwin" ]]; then
    echo "Windows";
elif [[ "$OSTYPE" == "msys" ]]; then
    echo "Windows";
elif [[ "$OSTYPE" == "win32" ]]; then
    echo "Windows"
elif [[ "$OSTYPE" == "freebsd"* ]]; then
    echo "FreeBSD";
else
    echo "unknown";
fi