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
   

You cannot combine any of the three ways to execute code.

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.