How to install and configure PHP
PHP is a general-purpose scripting language well-suited for Web development since PHP scripts can be embedded into HTML. This guide explains how to install and configure PHP in an Ubuntu System with Apache2 and MySQL.
Prerequisites
Before installing PHP you should install Apache (or a preferred web server) and a database service such as MySQL.
- To install the Apache package, please refer to our Apache guide.
- To install and configure a MySQL database service, refer to our MySQL guide.
Install PHP
PHP is available on Ubuntu Linux, but unlike Python (which comes pre-installed), must be manually installed.
To install PHP – and the Apache PHP module – you can enter the following command into a terminal prompt:
sudo apt install php libapache2-mod-php
Install optional packages
The following packages are optional, and can be installed if you need them for your setup.
- PHP-CLI
You can run PHP scripts via the Command Line Interface (CLI). To do this, you must first install the php-cli package. You can install it by running the following command:
sudo apt install php-mysql
sudo apt install php-pgsql
Configure PHP
If you have installed the libapache2-mod-php or php-cgi packages, you can run PHP scripts from your web browser. If you have installed the php-cli package, you can run PHP scripts at a terminal prompt.
By default, when libapache2-mod-php is installed, the Apache2 web server is configured to run PHP scripts using this module. First, verify if the files /etc/apache2/mods-enabled/php8.*.conf and /etc/apache2/mods-enabled/php8.*.load exist. If they do not exist, you can enable the module using the a2enmod command.
Once you have installed the PHP-related packages and enabled the Apache PHP module, you should restart the Apache2 web server to run PHP scripts, by running the following command:
sudo systemctl restart apache2.service
Test your setup
To verify your installation, you can run the following PHP phpinfo script:
You can save the content in a file – phpinfo.php for example – and place it under the DocumentRoot directory of the Apache2 web server. Pointing your browser to http://hostname/phpinfo.php will display the values of various PHP configuration parameters.
Further reading
- For more in depth information see the php.net documentation.
- There are a plethora of books on PHP 7 and PHP 8. A good book from O’Reilly is Learning PHP, which includes an exploration of PHP 7’s enhancements to the language.
- Also, see the Apache MySQL PHP Ubuntu Wiki page for more information.
Run php files on ubuntu
- Tell PHP to execute a certain file.
$ php my_script.php $ php -f my_script.php
$ php -r 'print_r(get_defined_constants());'
Note: Read the example carefully: there are no beginning or ending tags! The -r switch simply does not need them, and using them will lead to a parse error.
$ some_application | some_filter | php | sort -u > final_output.txt
As with every shell application, the PHP binary accepts a number of arguments; however, the PHP script can also receive further arguments. The number of arguments that can be passed to your script is not limited by PHP (and although the shell has a limit to the number of characters which can be passed, this is not in general likely to be hit). The arguments passed to the script are available in the global array $argv . The first index (zero) always contains the name of the script as called from the command line. Note that, if the code is executed in-line using the command line switch -r, the value of $argv[0] will be «Standard input code» ; prior to PHP 7.2.0, it was a dash ( «-» ) instead. The same is true if the code is executed via a pipe from STDIN .
A second global variable, $argc , contains the number of elements in the $argv array (not the number of arguments passed to the script).
As long as the arguments to be passed to the script do not start with the — character, there’s nothing special to watch out for. Passing an argument to the script which starts with a — will cause trouble because the PHP interpreter thinks it has to handle it itself, even before executing the script. To prevent this, use the argument list separator — . After this separator has been parsed by PHP, every following argument is passed untouched to the script.
# This will not execute the given code but will show the PHP usage $ php -r 'var_dump($argv);' -h Usage: php [options] [-f] [args. ] [. ] # This will pass the '-h' argument to the script and prevent PHP from showing its usage $ php -r 'var_dump($argv);' -- -h array(2) < [0]=>string(1) "-" [1]=> string(2) "-h" >
However, on Unix systems there’s another way of using PHP for shell scripting: make the first line of the script start with #!/usr/bin/php (or whatever the path to your PHP CLI binary is if different). The rest of the file should contain normal PHP code within the usual PHP starting and end tags. Once the execution attributes of the file are set appropriately (e.g. chmod +x test), the script can be executed like any other shell or perl script:
Example #1 Execute PHP script as shell script
Assuming this file is named test in the current directory, it is now possible to do the following:
$ chmod +x test $ ./test -h -- foo array(4) < [0]=>string(6) "./test" [1]=> string(2) "-h" [2]=> string(2) "--" [3]=> string(3) "foo" >
As can be seen, in this case no special care needs to be taken when passing parameters starting with — .
The PHP executable can be used to run PHP scripts absolutely independent of the web server. On Unix systems, the special #! (or «shebang») first line should be added to PHP scripts so that the system can automatically tell which program should run the script. On Windows platforms, it’s possible to associate php.exe with the double click option of the .php extension, or a batch file can be created to run scripts through PHP. The special shebang first line for Unix does no harm on Windows (as it’s formatted as a PHP comment), so cross platform programs can be written by including it. A simple example of writing a command line PHP program is shown below.
Example #2 Script intended to be run from command line (script.php)
if ( $argc != 2 || in_array ( $argv [ 1 ], array( ‘—help’ , ‘-help’ , ‘-h’ , ‘-?’ ))) ?>
This is a command line PHP script with one option.
can be some word you would like
to print out. With the —help, -help, -h,
or -? options, you can get this help.
The script above includes the Unix shebang first line to indicate that this file should be run by PHP. We are working with a CLI version here, so no HTTP headers will be output.
The program first checks that there is the required one argument (in addition to the script name, which is also counted). If not, or if the argument was —help, -help, -h or -?, the help message is printed out, using $argv[0] to dynamically print the script name as typed on the command line. Otherwise, the argument is echoed out exactly as received.
To run the above script on Unix, it must be made executable, and called simply as script.php echothis or script.php -h. On Windows, a batch file similar to the following can be created for this task:
Example #3 Batch file to run a command line PHP script (script.bat)
@echo OFF "C:\php\php.exe" script.php %*
Assuming the above program is named script.php , and the CLI php.exe is in C:\php\php.exe , this batch file will run it, passing on all appended options: script.bat echothis or script.bat -h.
See also the Readline extension documentation for more functions which can be used to enhance command line applications in PHP.
On Windows, PHP can be configured to run without the need to supply the C:\php\php.exe or the .php extension, as described in Command Line PHP on Microsoft Windows.
Note:
On Windows it is recommended to run PHP under an actual user account. When running under a network service certain operations will fail, because «No mapping between account names and security IDs was done».
User Contributed Notes 7 notes
On Linux, the shebang (#!) line is parsed by the kernel into at most two parts.
For example:
1: #!/usr/bin/php
2: #!/usr/bin/env php
3: #!/usr/bin/php -n
4: #!/usr/bin/php -ddisplay_errors=E_ALL
5: #!/usr/bin/php -n -ddisplay_errors=E_ALL
1. is the standard way to start a script. (compare «#!/bin/bash».)
2. uses «env» to find where PHP is installed: it might be elsewhere in the $PATH, such as /usr/local/bin.
3. if you don’t need to use env, you can pass ONE parameter here. For example, to ignore the system’s PHP.ini, and go with the defaults, use «-n». (See «man php».)
4. or, you can set exactly one configuration variable. I recommend this one, because display_errors actually takes effect if it is set here. Otherwise, the only place you can enable it is system-wide in php.ini. If you try to use ini_set() in your script itself, it’s too late: if your script has a parse error, it will silently die.
5. This will not (as of 2013) work on Linux. It acts as if the whole string, «-n -ddisplay_errors=E_ALL» were a single argument. But in BSD, the shebang line can take more than 2 arguments, and so it may work as intended.
Summary: use (2) for maximum portability, and (4) for maximum debugging.