linux set default php

1//In ubunutu
2Default PHP 7.1 is set on your system and you need to switch to PHP 5.6
3
4$ sudo a2dismod php7.1
5$ sudo a2enmod php5.6
6$ sudo service apache2 restart
7  
8sudo update-alternatives --set php /usr/bin/php5.6

1------------ Set Default PHP Version 7.0 ------------
2$ sudo update-alternatives --set php /usr/bin/php7.0
3

1$ sudo update-alternatives --config php
2 or
3$ sudo a2enmod php7.1(version)
4

1update-alternatives --set php /usr/bin/php7.4
2update-alternatives --set phar /usr/bin/phar7.4
3update-alternatives --set phar.phar /usr/bin/phar.phar7.4
4update-alternatives --set phpize /usr/bin/phpize7.4
5update-alternatives --set php-config /usr/bin/php-config7.4
6