Command for switching PHP versions [tested in Ubuntu only]

SwitchPhpCommand.php

<?php

namespace App\Command;

use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputArgument;
use Symfony\Component\Console\Input\InputDefinition;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Console\Output\OutputInterface;
use Symfony\Component\Console\Style\SymfonyStyle;
use Webmozart\Assert\Assert;

class SwitchPhpCommand extends Command
{
    /** @var string */
    protected static $defaultName = 'devtools:php:switch';

    /**
     * {@inheritdoc}
     */
    protected function configure()
    {
        $this
            ->setDefinition($this->createDefinition())
            ->setDescription('Switch php version.')
            ->addUsage('7.3')
            ->addUsage('7.1');
    }

    /**
     * {@inheritdoc}
     */
    public function getNativeDefinition()
    {
        return $this->createDefinition();
    }

    /**
     * {@inheritdoc}
     */
    protected function execute(InputInterface $input, OutputInterface $output)
    {
        $io = new SymfonyStyle($input, $output);
        $io->newLine();

        $phpVersion = $input->getArgument('version');
        $restartServices = $input->getOption('restart');
        $phpBin = sprintf('/usr/bin/php%s', $phpVersion);

        if (!file_exists($phpBin)) {
            $io->error(sprintf('PHP binary (%s) not found', $phpBin));

            return;
        }

        shell_exec(sprintf('sudo ln -sfn %s /etc/alternatives/php', $phpBin));

        if ($restartServices === true) {
            $command = sprintf('sudo service nginx restart && sudo service php%s-fpm restart', $phpVersion);
            $io->text(sprintf('Restarting services: <info>%s</info>', $command));
            shell_exec($command);
        }

        $phpVersionOutput = shell_exec('php -v');

        preg_match('/PHP (\d.\d.\d{1,2})/', $phpVersionOutput, $matches);

        Assert::isArray($matches);
        Assert::notEmpty($matches);
        Assert::keyExists($matches, 1);
        Assert::startsWith(
            $matches[1],
            $phpVersion,
            sprintf('PHP version not changed. Expected: %s, current: %s', $phpVersion, $matches[1])
        );

        $io->success(sprintf('PHP version successfully changed: %s', $matches[1]));
    }

    /**
     * {@inheritdoc}
     */
    private function createDefinition()
    {
        return new InputDefinition([
            new InputArgument('version', InputArgument::REQUIRED, 'PHP version.'),
            new InputOption('restart', null, InputOption::VALUE_REQUIRED, 'Restart nginx and php-fpm', true),
        ]);
    }
}