compile.php

<?php declare(strict_types=1);

try {
    $pharFile = 'app.phar';

    // clean up
    if (file_exists($pharFile)) {
        unlink($pharFile);
    }

    if (file_exists($pharFile . '.gz')) {
        unlink($pharFile . '.gz');
    }

    // create phar
    $phar = new Phar($pharFile);

    // start buffering. Mandatory to modify stub to add shebang
    $phar->startBuffering();

    // Create the default stub from main.php entrypoint
    $defaultStub = Phar::createDefaultStub('main.php');

    // Add the rest of the apps files
    $phar->buildFromDirectory(__DIR__ . '/app');

    // Customize the stub to add the shebang
    $stub = "#!/usr/bin/env php \n" . $defaultStub;

    // Add the stub
    $phar->setStub($stub);

    $phar->stopBuffering();

    // plus - compressing it into gzip
    $phar->compressFiles(Phar::GZ);

    # Make the file executable
    chmod(__DIR__ . '/app.phar', 0770);

    echo "$pharFile successfully created" . PHP_EOL;
} catch (\Throwable $e) {
    echo $e->getMessage();
}