Script to change rapidly the php version, from x version to y version

switch_php_version.sh

#!/bin/bash

showHelp() {
    echo ""
    echo Missing parameters, Needs two parameters -f --from PHP version, and -t --to PHP version
    echo -e '\t' Example:
    echo -e '\t' $0 -f 5.6 -t 7.3
    exit 1
}

isNumber(){

    re='^[0-9]+([.][0-9]+)?$'
    if ! [[ $parameterFrom =~ $re ]] && [[ $parameterTo =~ $re ]] ; then
       echo "error: Not a number" >&2; exit 1
    fi

}


while getopts "f:t:" opt
do
   case "$opt" in
      f ) parameterFrom="$OPTARG" ;;
      t ) parameterTo="$OPTARG" ;;
      ? ) showHelp ;;
   esac
done

isNumber

sudo a2dismod php$parameterFrom && sudo a2enmod php$parameterTo && sudo service apache2 restart &&
sudo update-alternatives --set php /usr/bin/php$parameterTo && sudo update-alternatives --set phar /usr/bin/phar$parameterTo &&
sudo update-alternatives --set phar.phar /usr/bin/phar.phar$parameterTo && sudo update-alternatives --set phpize /usr/bin/phpize$parameterTo &&
sudo update-alternatives --set php-config /usr/bin/php-config$parameterTo

echo DONE!
echo ""
php -v