Executing PHP files

There are three different ways of supplying the CLI SAPI with PHP code to be executed:

1. Tell PHP to execute a certain file.

   $ php my_script.php
   
   $ php -f my_script.php
   

   Both ways (whether using the -f switch or not) execute the file my_script.php. Note that there is no restriction on which files can be executed; in particular, the filename is not required have a .php extension.

   Note:

   If arguments need to be passed to the script when using -f, the first argument must be --.

2. Pass the PHP code to execute directly on the command line.

   $ php -r 'print_r(get_defined_constants());'
   

   Special care has to be taken with regard to shell variable substitution and usage of quotes.

   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.

3. Provide the PHP code to execute via standard input (stdin).

   This gives the powerful ability to create PHP code dynamically and feed it to the binary, as shown in this (fictional) example:

   $ 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 just a dash (-). 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] <file> [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:

$ 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.

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:

@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".