php swicher credit to https://bbs.archlinux.org/viewtopic.php?id=263999

php_swich.sh

#!/bin/sh
[ "$#" -lt "1" ] && {
  echo "Configure current shell to use a specific major PHP version.

    Usage: usephp 7"
  exit 0
}
binary="php${1}"
wanted="/usr/bin/${binary}"
[ ! -f "${wanted}" ] && {
  echo "'${binary}' not found. Using 'php'."
  wanted="/usr/bin/php"
}
ln -sf "${wanted}" "${HOME}/bin/php"
inUse=$(php -nr "echo phpversion();")
echo "Shell configured to use PHP ${inUse}."