PHP CLI vs web server execution - Practice Questions

Challenge - 5 Problems

❓ Predict Output

intermediate

Output difference between CLI and web server

What is the output of this PHP code when run from the command line (CLI) versus when accessed via a web server?

PHP

<?php
if (php_sapi_name() === 'cli') {
    echo "Running in CLI mode";
} else {
    echo "Running in Web Server mode";
}

A Running in CLI modeRunning in Web Server mode

B Running in Web Server mode

C No output

D Running in CLI mode

💡 Hint

php_sapi_name() returns the interface PHP is using.

php_sapi_name() returns 'cli' when run from the command line, so the code prints 'Running in CLI mode'. When run via a web server, it returns something else like 'apache2handler'.

🧠 Conceptual

intermediate

PHP environment variables in CLI vs Web Server

Which statement about environment variables in PHP CLI and web server execution is true?

A Environment variables in CLI are inherited from the shell, but web server variables depend on server configuration.

B Environment variables are always the same in CLI and web server modes.

C PHP CLI cannot access environment variables.

D Web server execution always has fewer environment variables than CLI.

💡 Hint

Think about where PHP gets environment variables in each mode.

In CLI mode, PHP inherits environment variables from the shell or terminal. In web server mode, environment variables depend on the server's configuration and may differ.

🔧 Debug

advanced

Why does PHP script behave differently in CLI and web server?

A PHP script uses $_SERVER['REQUEST_METHOD'] to check the HTTP method. It works fine on the web server but throws an error in CLI. Why?

PHP

<?php
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
    echo "Form submitted";
} else {
    echo "Show form";
}

A In CLI, $_SERVER['REQUEST_METHOD'] is not set, causing an undefined index error.

B CLI does not support POST requests, so the script crashes.

C The script needs a special CLI flag to access $_SERVER variables.

D The web server disables $_SERVER variables in CLI mode.

💡 Hint

Check if $_SERVER['REQUEST_METHOD'] exists in CLI mode.

$_SERVER['REQUEST_METHOD'] is set only in web server context during HTTP requests. In CLI, it is not set, so accessing it causes an undefined index error.

📝 Syntax

advanced

Which PHP code snippet correctly detects CLI mode?

Choose the code snippet that correctly detects if PHP is running in CLI mode.

A if (php_sapi_name() == 'cli') { echo 'CLI'; }

B if (PHP_SAPI === 'cli') { echo 'CLI'; }

C if (php_sapi_name() = 'cli') { echo 'CLI'; }

D if (PHP_SAPI == 'CLI') { echo 'CLI'; }

💡 Hint

Check for correct comparison operator and case sensitivity.

PHP_SAPI is a predefined constant with the current interface name. Comparing it with 'cli' using === is correct. Option B uses == which works but === is preferred. Option B uses assignment = instead of comparison. Option B compares with uppercase 'CLI' which is incorrect.

🚀 Application

expert

How to write a PHP script that behaves differently in CLI and web server?

You want a PHP script to print 'Hello CLI' when run from command line and 'Hello Web' when accessed via web server. Which code achieves this?

A

<?php
if (isset($_SERVER['HTTP_HOST'])) {
    echo 'Hello CLI';
} else {
    echo 'Hello Web';
}

B

<?php
if (PHP_SAPI == 'web') {
    echo 'Hello Web';
} else {
    echo 'Hello CLI';
}

C

<?php
if (php_sapi_name() === 'cli') {
    echo 'Hello CLI';
} else {
    echo 'Hello Web';
}

D

<?php
if (php_sapi_name() === 'cgi') {
    echo 'Hello CLI';
} else {
    echo 'Hello Web';
}

💡 Hint

Use php_sapi_name() to detect CLI mode exactly.

php_sapi_name() returns 'cli' when run from command line. Option C correctly checks for 'cli' and prints accordingly. Option C checks for 'web' which is not a valid sapi name. Option C reverses logic and misuses $_SERVER['HTTP_HOST']. Option C checks for 'cgi' which is not CLI.