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# Chapter 43. Using PHP from the command line

As of version 4.3.0, PHP supports a new SAPI type (Server Application Programming Interface) named CLI which means Command Line Interface. As the name implies, this SAPI type main focus is on developing shell (or desktop as well) applications with PHP. There are quite a few differences between the CLI SAPI and other SAPIs which are explained in this chapter. It's worth mentioning that CLI and CGI are different SAPI's although they do share many of the same behaviors.

The CLI SAPI was released for the first time with PHP 4.2.0, but was still experimental and had to be explicitly enabled with --enable-cli when running ./configure. Since PHP 4.3.0 the CLI SAPI is no longer experimental and the option --enable-cli is on by default. You may use --disable-cli to disable it.

As of PHP 4.3.0, the name, location and existence of the CLI/CGI binaries will differ depending on how PHP is installed on your system. By default when executing make, both the CGI and CLI are built and placed as `sapi/cgi/php` and `sapi/cli/php` respectively, in your PHP source directory. You will note that both are named php. What happens during make install depends on your configure line. If a module SAPI is chosen during configure, such as apxs, or the --disable-cgi option is used, the CLI is copied to `{PREFIX}/bin/php` during make install otherwise the CGI is placed there. So, for example, if --with--apxs is in your configure line then the CLI is copied to `{PREFIX}/bin/php` during make install. If you want to override the installation of the CGI binary, use make install-cli after make install. Alternatively you can specify --disable-cgi in your configure line.

> Note: Because both --enable-cli and --enable-cgi are enabled by default, simply having --enable-cli in your configure line does not necessarily mean the CLI will be copied as `{PREFIX}/bin/php` during make install.

The windows packages between PHP 4.2.0 and PHP 4.2.3 distributed the CLI as `php-cli.exe`, living in the same folder as the CGI `php.exe`. Starting with PHP 4.3.0 the windows package distributes the CLI as `php.exe` in a separate folder named `cli`, so `cli/php.exe` . Starting with PHP 5, the CLI is distributed in the main folder, named `php.exe`. The CGI version is distributed as `php-cgi.exe`.

As of PHP 5, a new `php-win.exe` file is distributed. This is equal to the CLI version, except that php-win doesn't output anything and thus provides no console (no "dos box" appears on the screen). This behavior is similar to php-gtk. You should configure with --enable-cli-win32.

> What SAPI do I have?: From a shell, typing php -v will tell you whether `php` is CGI or CLI. See also the function php_sapi_name() and the constant `PHP_SAPI`.

> Note: A Unix manual page was added in PHP 4.3.2. You may view this by typing man php in your shell environment.

Remarkable differences of the CLI SAPI compared to other SAPIs:

- Unlike the CGI SAPI, no headers are written to the output.

  Though the CGI SAPI provides a way to suppress HTTP headers, there's no equivalent switch to enable them in the CLI SAPI.

  CLI is started up in quiet mode by default, though the -q and --no-header switches are kept for compatibility so that you can use older CGI scripts.

  It does not change the working directory to that of the script. (-C and --no-chdir switches kept for compatibility)

  Plain text error messages (no HTML formatting).

- There are certain `php.ini` directives which are overridden by the CLI SAPI because they do not make sense in shell environments:

  Table 43-1. Overridden `php.ini` directives

  Directive | CLI SAPI default value | Comment
  --- | --- | ---
  html_errors | `FALSE` | It can be quite hard to read the error message in your shell when it's cluttered with all those meaningless HTML tags, therefore this directive defaults to `FALSE`.
  implicit_flush | `TRUE` | It is desired that any output coming from print(), echo() and friends is immediately written to the output and not cached in any buffer. You still can use output buffering if you want to defer or manipulate standard output.
  max_execution_time | 0 (unlimited) | Due to endless possibilities of using PHP in shell environments, the maximum execution time has been set to unlimited. Whereas applications written for the web are often executed very quickly, shell application tend to have a much longer execution time.
  register_argc_argv | `TRUE` | Because this setting is `TRUE` you will always have access to argc (number of arguments passed to the application) and argv (array of the actual arguments) in the CLI SAPI. As of PHP 4.3.0, the PHP variables $argc and $argv are registered and filled in with the appropriate values when using the CLI SAPI. Prior to this version, the creation of these variables behaved as they do in CGI and MODULE versions which requires the PHP directive register_globals to be on. Regardless of version or register_globals setting, you can always go through either $_SERVER or $HTTP_SERVER_VARS. Example: $_SERVER['argv']

  > Note: These directives cannot be initialized with another value from the configuration file `php.ini` or a custom one (if specified). This is a limitation because those default values are applied after all configuration files have been parsed. However, their value can be changed during runtime (which does not make sense for all of those directives, e.g. register_argc_argv).

- To ease working in the shell environment, the following constants are defined:

  Table 43-2. CLI specific Constants

  Constant | Description
  --- | ---
  `STDIN` | An already opened stream to stdin. This saves opening it with
  `<?php $stdin = fopen('php://stdin', 'r'); ?>`
  If you want to read single line from stdin, you can use
  `<?php $line = trim(fgets(STDIN)); // reads one line from STDIN fscanf(STDIN, "%d\n", $number); // reads number from STDIN ?>`
  `STDOUT` | An already opened stream to stdout. This saves opening it with
  `<?php $stdout = fopen('php://stdout', 'w'); ?>`
  `STDERR` | An already opened stream to stderr. This saves opening it with
  `<?php $stderr = fopen('php://stderr', 'w'); ?>`

  Given the above, you don't need to open e.g. a stream for stderr yourself but simply use the constant instead of the stream resource:

      php -r 'fwrite(STDERR, "stderr\n");'

  You do not need to explicitly close these streams, as they are closed automatically by PHP when your script ends.

- The CLI SAPI does not change the current directory to the directory of the executed script!

  Example showing the difference to the CGI SAPI:

  `<?php // Our simple test application named test.php echo getcwd(), "\n"; ?>`

  When using the CGI version, the output is:

      $ pwd
      /tmp

      $ php -q another_directory/test.php
      /tmp/another_directory

  This clearly shows that PHP changes its current directory to the one of the executed script.

  Using the CLI SAPI yields:

      $ pwd
      /tmp

      $ php -f another_directory/test.php
      /tmp

  This allows greater flexibility when writing shell tools in PHP.

  > Note: The CGI SAPI supports this CLI SAPI behaviour by means of the -C switch when run from the command line.

The list of command line options provided by the PHP binary can be queried anytime by running PHP with the -h switch:

    Usage: php [options] [-f] <file> [--] [args...]
           php [options] -r <code> [--] [args...]
           php [options] [-B <begin_code>] -R <code> [-E <end_code>] [--] [args...]
           php [options] [-B <begin_code>] -F <file> [-E <end_code>] [--] [args...]
           php [options] -- [args...]
           php [options] -a

      -a               Run interactively
      -c <path>|<file> Look for php.ini file in this directory
      -n               No php.ini file will be used
      -d foo[=bar]     Define INI entry foo with value 'bar'
      -e               Generate extended information for debugger/profiler
      -f <file>        Parse <file>.
      -h               This help
      -i               PHP information
      -l               Syntax check only (lint)
      -m               Show compiled in modules
      -r <code>        Run PHP <code> without using script tags <?..?>
      -B <begin_code>  Run PHP <begin_code> before processing input lines
      -R <code>        Run PHP <code> for every input line
      -F <file>        Parse and execute <file> for every input line
      -E <end_code>    Run PHP <end_code> after processing all input lines
      -H               Hide any passed arguments from external tools.
      -s               Display colour syntax highlighted source.
      -v               Version number
      -w               Display source with stripped comments and whitespace.
      -z <file>        Load Zend extension <file>.

      args...          Arguments passed to script. Use -- args when first argument
                       starts with - or script is read from stdin

The CLI SAPI has three different ways of getting the PHP code you want to execute:

1. Telling 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`. You can choose any file to execute - your PHP scripts do not have to end with the .php extension but can have any name or extension you wish.

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 in regards of shell variable substitution and quoting usage.

   > Note: Read the example carefully, there are no beginning or ending tags! The -r switch simply does not need them. Using them will lead to a parser error.

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

   This gives the powerful ability to dynamically create PHP code 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.

Like every shell application, the PHP binary accepts a number of arguments but your PHP script can also receive arguments. The number of arguments which can be passed to your script is not limited by PHP (the shell has a certain size limit in the number of characters which can be passed; usually you won't hit this limit). The arguments passed to your script are available in the global array $argv. The zero index always contains the script name (which is - in case the PHP code is coming from either standard input or from the command line switch -r). The second registered global variable is $argc which contains the number of elements in the $argv array (not the number of arguments passed to the script).

As long as the arguments you want to pass to your script do not start with the - character, there's nothing special to watch out for. Passing an argument to your script which starts with a - will cause trouble because PHP itself thinks it has to handle it. To prevent this, use the argument list separator --. After this separator has been parsed by PHP, every argument following it is passed untouched to your 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 your script and prevent PHP from showing it's usage
    $ php -r 'var_dump($argv);' -- -h
    array(2) {
      [0]=>
      string(1) "-"
      [1]=>
      string(2) "-h"
    }

However, there's another way of using PHP for shell scripting. You can write a script where the first line starts with #!/usr/bin/php. Following this you can place normal PHP code included within the PHP starting and end tags. Once you have set the execution attributes of the file appropriately (e.g. chmod +x test) your script can be executed like a normal shell or perl script:

`#!/usr/bin/php <?php var_dump($argv); ?>`

Assuming this file is named `test` in the current directory, we can now 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 you see, in this case no care needs to be taken when passing parameters which start with - to your script.

Long options are available since PHP 4.3.3.

Table 43-3. Command line options

Option | Long Option | Description
--- | --- | ---
-a | --interactive | Runs PHP interactively. If you compile PHP with the Readline extension (which is not available on windows), you'll have a nice shell, including a completion feature (e.g. you can start typing a variable name, hit the TAB key and PHP completes its name) and a typing history that can be accessed using the arrow keys. The history is saved in the `~/.php_history` file. Note: Files included through auto_prepend_file and auto_append_file are parsed in this mode but with some restrictions - e.g. functions have to be defined before called.
-c | --php-ini | With this option one can either specify a directory where to look for `php.ini` or you can specify a custom INI file directly (which does not need to be named `php.ini`), e.g.:
    $ php -c /custom/directory/ my_script.php

    $ php -c /custom/directory/custom-file.ini my_script.php
If you don't specify this option, file is searched in default locations.
-n | --no-php-ini | Ignore `php.ini` at all. This switch is available since PHP 4.3.0.
-d | --define | This option allows you to set a custom value for any of the configuration directives allowed in `php.ini`. The syntax is:
    -d configuration_directive[=value]
Examples (lines are wrapped for layout reasons):
    # Omitting the value part will set the given configuration directive to "1"
    $ php -d max_execution_time
            -r '$foo = ini_get("max_execution_time"); var_dump($foo);'
    string(1) "1"

    # Passing an empty value part will set the configuration directive to ""
    php -d max_execution_time=
            -r '$foo = ini_get("max_execution_time"); var_dump($foo);'
    string(0) ""

    # The configuration directive will be set to anything passed after the '=' character
    $  php -d max_execution_time=20
            -r '$foo = ini_get("max_execution_time"); var_dump($foo);'
    string(2) "20"
    $  php
            -d max_execution_time=doesntmakesense
            -r '$foo = ini_get("max_execution_time"); var_dump($foo);'
    string(15) "doesntmakesense"
-e | --profile-info | Activate the extended information mode, to be used by a debugger/profiler.
-f | --file | Parses and executed the given filename to the -f option. This switch is optional and can be left out. Only providing the filename to execute is sufficient.
-h and -? | --help and --usage | With this option, you can get information about the actual list of command line options and some one line descriptions about what they do.
-i | --info | This command line option calls phpinfo(), and prints out the results. If PHP is not working correctly, it is advisable to use php -i and see whether any error messages are printed out before or in place of the information tables. Beware that when using the CGI mode the output is in HTML and therefore quite huge.
-l | --syntax-check | This option provides a convenient way to only perform a syntax check on the given PHP code. On success, the text No syntax errors detected in <filename> is written to standard output and the shell return code is 0. On failure, the text Errors parsing <filename> in addition to the internal parser error message is written to standard output and the shell return code is set to 255. This option won't find fatal errors (like undefined functions). Use -f if you would like to test for fatal errors too. Note: This option does not work together with the -r option.
-m | --modules | Using this option, PHP prints out the built in (and loaded) PHP and Zend modules:
    $ php -m
    [PHP Modules]
    xml
    tokenizer
    standard
    session
    posix
    pcre
    overload
    mysql
    mbstring
    ctype

    [Zend Modules]
> -r | --run | This option allows execution of PHP right from within the command line. The PHP start and end tags (<?php and ?>) are not needed and will cause a parser error if present. Note: Care has to be taken when using this form of PHP to not collide with command line variable substitution done by the shell. Example showing a parser error
>     $ php -r "$foo = get_defined_constants();"
>     Command line code(1) : Parse error - parse error, unexpected '='
> The problem here is that the sh/bash performs variable substitution even when using double quotes ". Since the variable $foo is unlikely to be defined, it expands to nothing which results in the code passed to PHP for execution actually reading:
>     $ php -r " = get_defined_constants();"
> The correct way would be to use single quotes '. Variables in single-quoted strings are not expanded by sh/bash.
>     $ php -r '$foo = get_defined_constants(); var_dump($foo);'
>     array(370) {
>       ["E_ERROR"]=>
>       int(1)
>       ["E_WARNING"]=>
>       int(2)
>       ["E_PARSE"]=>
>       int(4)
>       ["E_NOTICE"]=>
>       int(8)
>       ["E_CORE_ERROR"]=>
>       [...]
If you are using a shell different from sh/bash, you might experience further issues. Feel free to open a bug report at http://bugs.php.net/. One can still easily run into troubles when trying to get shell variables into the code or using backslashes for escaping. You've been warned. Note: -r is available in the CLI SAPI and not in the CGI SAPI. Note: This option is meant for a very basic stuff. Thus some configuration directives (e.g. auto_prepend_file and auto_append_file) are ignored in this mode.
-B | --process-begin | PHP code to execute before processing stdin. Added in PHP 5.
-R | --process-code | PHP code to execute for every input line. Added in PHP 5. There are two special variables available in this mode: $argn and $argi. $argn will contain the line PHP is processing at that moment, while $argi will contain the line number.
-F | --process-file | PHP file to execute for every input line. Added in PHP 5.
-E | --process-end | PHP code to execute after processing the input. Added in PHP 5. Example of using -B, -R and -E options to count the number of lines of a project.
    $ find my_proj | php -B '$l=0;' -R '$l += count(@file($argn));' -E 'echo "Total Lines: $l\n";'
    Total Lines: 37328
-s | --syntax-highlight and --syntax-highlight | Display colour syntax highlighted source. This option uses the internal mechanism to parse the file and produces a HTML highlighted version of it and writes it to standard output. Note that all it does it to generate a block of <code> [...] </code> HTML tags, no HTML headers. Note: This option does not work together with the -r option.
-v | --version | Writes the PHP, PHP SAPI, and Zend version to standard output, e.g.
    $ php -v
    PHP 4.3.0 (cli), Copyright (c) 1997-2002 The PHP Group
    Zend Engine v1.3.0, Copyright (c) 1998-2002 Zend Technologies
-w | --strip | Display source with stripped comments and whitespace. Note: This option does not work together with the -r option.
-z | --zend-extension | Load Zend extension. If only a filename is given, PHP tries to load this extension from the current default library path on your system (usually specified `/etc/ld.so.conf` on Linux systems). Passing a filename with an absolute path information will not use the systems library search path. A relative filename with a directory information will tell PHP only to try to load the extension relative to the current directory.

The PHP executable can be used to run PHP scripts absolutely independent from the web server. If you are on a Unix system, you should add a special first line to your PHP script, and make it executable, so the system will know, what program should run the script. On a Windows platform you can associate `php.exe` with the double click option of the .php files, or you can make a batch file to run the script through PHP. The first line added to the script to work on Unix won't hurt on Windows, so you can write cross platform programs this way. A simple example of writing a command line PHP program can be found below.

Example 43-1. Script intended to be run from command line (script.php)
`#!/usr/bin/php <?php if ($argc != 2 || in_array($argv[1], array('--help', '-help', '-h', '-?'))) { ?> This is a command line PHP script with one option. Usage: <?php echo $argv[0]; ?> <option> <option> can be some word you would like to print out. With the --help, -help, -h, or -? options, you can get this help. <?php } else { echo $argv[1]; } ?>`

In the script above, we used the special first line to indicate that this file should be run by PHP. We work with a CLI version here, so there will be no HTTP header printouts. There are two variables you can use while writing command line applications with PHP: $argc and $argv. The first is the number of arguments plus one (the name of the script running). The second is an array containing the arguments, starting with the script name as number zero ($argv[0]).

In the program above we checked if there are less or more than one arguments. Also if the argument was --help, -help, -h or -?, we printed out the help message, printing the script name dynamically. If we received some other argument we echoed that out.

If you would like to run the above script on Unix, you need to make it executable, and simply call it as script.php echothis or script.php -h. On Windows, you can make a batch file for this task:

Example 43-2. Batch file to run a command line PHP script (script.bat)
    @C:\php\php.exe script.php %1 %2 %3 %4

Assuming you named the above program `script.php`, and you have your CLI `php.exe` in `C:\php\php.exe` this batch file will run it for you with your added options: script.bat echothis or script.bat -h.

See also the Readline extension documentation for more functions you can use to enhance your command line applications in PHP.

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