Many developers assume PHP requires Apache due to historical LAMP stack conventions, but PHP can run independently as a CLI (Command Line Interface) tool or via other web servers like Nginx. The key is installing the core PHP package without Apache modules.

First, update your package lists:

sudo apt-get update

Then install the minimal PHP5 CLI package:

sudo apt-get install php5-cli

For development purposes, you might want common extensions:

sudo apt-get install php5-common php5-mysql php5-curl php5-gd

Create a test file (test.php) with:

<?php
phpinfo();
?>

Run it via CLI to confirm:

php test.php

If using Nginx, install PHP-FPM:

sudo apt-get install php5-fpm

Configure Nginx to process PHP files by adding to server block:

location ~ \.php$ {
    include snippets/fastcgi-php.conf;
    fastcgi_pass unix:/var/run/php5-fpm.sock;
}

Avoid these mistakes:

• Installing libapache2-mod-php5 (this pulls in Apache)
• Assuming CGI mode requires Apache
• Not configuring alternative web servers properly

Standalone PHP5 typically uses less memory than Apache-module installations. Benchmark with:

ab -n 1000 -c 100 http://yourserver/test.php

---

Many developers assume PHP requires Apache or other web servers, but PHP can run as a standalone CLI (Command Line Interface) interpreter. This separation is particularly useful for:

• Writing standalone PHP scripts
• Running background jobs/cron tasks
• Testing code without web server overhead
• Building command-line tools

For Ubuntu systems, you have two primary approaches:

Method 1: Using apt-get (Recommended)

sudo apt-get update
sudo apt-get install php5-cli php5-common

Method 2: Compiling from Source

wget http://php.net/distributions/php-5.6.40.tar.gz
tar -xvzf php-5.6.40.tar.gz
cd php-5.6.40/
./configure --prefix=/usr/local/php5 --without-apache
make
sudo make install

Check your PHP CLI version:

php -v

Create a test script:

echo '' > test.php
php test.php

Edit php.ini for CLI-specific settings:

sudo nano /etc/php5/cli/php.ini

Key parameters to consider:

memory_limit = 256M
max_execution_time = 300
error_reporting = E_ALL
display_errors = On

Running Scheduled Tasks

# Add to crontab -e
* * * * * /usr/bin/php /path/to/your/script.php

Creating CLI Tools

#!/usr/bin/php
\n";
    exit(1);
}
echo "Hello, {$argv[1]}!\n";
?>

Make it executable:

chmod +x hello.php
./hello.php "Developer"

• Missing Extensions: Install with sudo apt-get install php5-{extension-name}
• Path Issues: Verify PHP location with which php
• Permission Problems: Run scripts with proper user privileges