PHP CLI vs web server execution - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to print "Hello from CLI" only when running PHP from the command line.

PHP

<?php
if (php_sapi_name() === [1]) {
    echo "Hello from CLI\n";
}
?>

Drag options to blanks, or click blank then click option'

A"cli"

B"cgi"

C"apache"

D"fpm"

Attempts:

3 left

💡 Hint

Common Mistakes

Using "apache" or "cgi" instead of "cli" causes the condition to fail.

The function php_sapi_name() returns the interface type. "cli" means running from command line.

2fill in blank

medium

Complete the code to get the current script name differently for CLI and web server.

PHP

<?php
if (php_sapi_name() === "cli") {
    $script = [1];
} else {
    $script = $_SERVER['SCRIPT_NAME'];
}
echo $script . "\n";
?>

Drag options to blanks, or click blank then click option'

A$_SERVER['SCRIPT_FILENAME']

B$_SERVER['PHP_SELF']

C$argv[0]

D$argv[1]

Attempts:

3 left

💡 Hint

Common Mistakes

Using $_SERVER variables in CLI mode returns empty or undefined.

In CLI mode, $argv[0] holds the script filename.

3fill in blank

hard

Fix the error in the code to detect if PHP runs via web server or CLI.

PHP

<?php
if (PHP_SAPI == [1]) {
    echo "Running in CLI mode\n";
} else {
    echo "Running in web server mode\n";
}
?>

Drag options to blanks, or click blank then click option'

A"cli"

Bcli

C"CLI"

D'cli'

Attempts:

3 left

💡 Hint

Common Mistakes

Omitting quotes causes a syntax error or undefined constant error.

PHP_SAPI is a string constant, so it must be compared to a string literal "cli" with double quotes.

4fill in blank

hard

Fill both blanks to create an array with script name and execution mode.

PHP

<?php
$info = [
    'script' => [1],
    'mode' => php_sapi_name() [2] "cli" ? 'CLI' : 'Web'
];
print_r($info);
?>

Drag options to blanks, or click blank then click option'

A$argv[0]

B===

C==

D$_SERVER['SCRIPT_NAME']

Attempts:

3 left

💡 Hint

Common Mistakes

Using == instead of === can cause unexpected results.

Use $argv[0] for script name in CLI and strict equality === for comparison.

5fill in blank

hard

Fill all three blanks to create a message showing execution mode and script name.

PHP

<?php
$mode = php_sapi_name() [1] "cli" ? 'CLI' : 'Web';
$name = [2];
$message = "Running in [3] mode: $name\n";
echo $message;
?>

Drag options to blanks, or click blank then click option'

A==

B$argv[0]

C$_SERVER['SCRIPT_NAME']

Dcli

E"CLI"

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong comparison operator or wrong variable for script name.

Use == to compare, $argv[0] for script name in CLI, and the string 'CLI' in the message.

Practice

1. Which statement best describes PHP CLI execution?

easy

A. It runs PHP scripts directly in the terminal without a browser.

B. It requires a web browser to execute PHP scripts.

C. It only works when accessed through a web server.

D. It is used exclusively for rendering HTML pages.

Solution

1. Step 1: Understand PHP CLI context

   PHP CLI means running PHP scripts directly from the command line interface (terminal), not through a browser.

2. Step 2: Compare with web server execution

   Web server execution requires a browser to request PHP pages, unlike CLI which runs standalone scripts.

3. Final Answer:

   It runs PHP scripts directly in the terminal without a browser. -> Option A

4. Quick Check:

   PHP CLI = Terminal execution [OK]

Hint: CLI means command line, no browser needed [OK]

Common Mistakes:

• Thinking CLI needs a browser
• Confusing CLI with web server mode
• Assuming CLI only renders HTML

2. Which PHP code snippet correctly checks if the script is running in CLI mode?

easy

A. if (php_sapi_name() == 'web') { echo 'CLI mode'; }

B. if ($_SERVER['REQUEST_METHOD'] == 'CLI') { echo 'CLI mode'; }

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

D. if (isset($_GET['cli'])) { echo 'CLI mode'; }

Solution

1. Step 1: Identify correct function for checking CLI

   php_sapi_name() returns the interface type; 'cli' means command line interface.

2. Step 2: Validate condition logic

   if (php_sapi_name() == 'cli') { echo 'CLI mode'; } correctly compares php_sapi_name() to 'cli' to detect CLI mode.

3. Final Answer:

   if (php_sapi_name() == 'cli') { echo 'CLI mode'; } -> Option C

4. Quick Check:

   php_sapi_name() == 'cli' detects CLI [OK]

Hint: Use php_sapi_name() == 'cli' to detect CLI [OK]

Common Mistakes:

• Using $_SERVER['REQUEST_METHOD'] for CLI detection
• Checking for 'web' instead of 'cli'
• Relying on GET parameters to detect CLI

3. What will be the output when running this PHP script via CLI?

if (php_sapi_name() == 'cli') {
    echo "Running in CLI";
} else {
    echo "Running on Web Server";
}

medium

A. Running in CLI

B. Running on Web Server

C. No output

D. Syntax error

Solution

1. Step 1: Check php_sapi_name() value in CLI

   When run in CLI, php_sapi_name() returns 'cli'.

2. Step 2: Evaluate the if condition

   The condition is true, so it echoes "Running in CLI".

3. Final Answer:

   Running in CLI -> Option A

4. Quick Check:

   php_sapi_name() == 'cli' true in CLI [OK]

Hint: php_sapi_name() returns 'cli' in terminal [OK]

Common Mistakes:

• Assuming it prints 'Running on Web Server' in CLI
• Expecting no output
• Confusing syntax error with runtime output

4. Identify the error in this PHP script intended to run only on CLI:

if (php_sapi_name() = 'cli') {
    echo "CLI mode";
} else {
    echo "Web mode";
}

medium

A. No error, script runs fine

B. php_sapi_name() cannot be used in CLI

C. Missing semicolon after echo statements

D. Using single equals (=) instead of double equals (==) in condition

Solution

1. Step 1: Check the condition operator

   The condition uses single equals (=), which is assignment, not comparison.

2. Step 2: Understand correct comparison syntax

   To compare values, double equals (==) must be used.

3. Final Answer:

   Using single equals (=) instead of double equals (==) in condition -> Option D

4. Quick Check:

   Use == for comparison, not = [OK]

Hint: Use == to compare, = is assignment [OK]

Common Mistakes:

• Confusing = with == in if conditions
• Thinking php_sapi_name() is unavailable in CLI
• Ignoring missing semicolons (they are present here)

5. You want to write a PHP script that behaves differently when run via CLI or web server. Which approach correctly implements this behavior?

hard

A. Check if $_SERVER['HTTP_HOST'] is set to detect web server mode.

B. Use php_sapi_name() to detect 'cli' and branch logic accordingly.

C. Use isset($_GET) to decide if running on web server.

D. Run the script twice, once in CLI and once in web server.

Solution

1. Step 1: Understand how to detect execution environment

   php_sapi_name() returns 'cli' for CLI mode, which is reliable for branching logic.

2. Step 2: Evaluate other options

   Checking $_SERVER['HTTP_HOST'] or $_GET is less reliable; running script twice is inefficient.

3. Final Answer:

   Use php_sapi_name() to detect 'cli' and branch logic accordingly. -> Option B

4. Quick Check:

   php_sapi_name() detects CLI vs web [OK]

Hint: Detect CLI with php_sapi_name() for branching [OK]

Common Mistakes:

• Relying on $_GET or $_SERVER variables that may not exist
• Running script multiple times unnecessarily
• Assuming HTTP_HOST is always set in web server