Checks package managers to determine which to use.

checkOS

#!/usr/bin/env bash

OS=""

if [[ -n $(command -v brew) ]]; then
  OS="OSX"
elif [[ -n $(command -v yum) ]]; then
  OS="RH"
elif [[ -n $(command -v apt-get) ]]; then
  OS="DEB"
elif [[ -n $(command -v pacman) ]]; then
  OS="ARCH"
elif [[ -n $(command -v emerge) ]]; then
  OS="GENTOO"
else
  OS="UNKNOWN"
fi

echo "$OS"