# PHP Command Line Interface (CLI)

PHP is not just for web pages; it can also be run from the command line to create scripts, cron jobs, and utilities.

---

## 1. Running Scripts
To run a PHP script from the command line, use the `php` command followed by the filename.

```bash
php script.php
```

## 2. Command Line Arguments
PHP provides two special variables to handle arguments passed to a script:
*   `$argc`: The number of arguments passed (integer).
*   `$argv`: An array of the arguments. Note that `$argv[0]` is always the name of the script itself.

**script.php:**
```php
<?php
echo "Script name: " . $argv[0] . "\n";
if ($argc > 1) {
    echo "Hello, " . $argv[1] . "!\n";
}
?>
```

**Command:**
```bash
php script.php John
```

**Output:**
```
Script name: script.php
Hello, John!
```

## 3. Interactive Input (STDIN)
You can read input from the user using the `STDIN` constant or `readline()`.

```php
echo "Are you sure you want to continue? (y/n): ";
$input = trim(fgets(STDIN));

if ($input == 'y') {
    echo "Continuing...\n";
} else {
    echo "Aborted.\n";
}
```

## 4. Built-in Web Server
PHP has a built-in web server useful for local testing without installing Apache or Nginx.

```bash
# Start server on localhost port 8000
php -S localhost:8000
```

## 5. Common Flags
*   `php -v`: Check PHP version.
*   `php -a`: Interactive shell (REPL).
*   `php -i`: Display PHP configuration (phpinfo).
*   `php -l file.php`: Syntax check (lint) a file.

[[programming/php/php]]