PHP: Interactive shell

Interactive shell

The CLI SAPI provides an interactive shell using the -a option if PHP is compiled with the --with-readline option. As of PHP 7.1.0 the interactive shell is also available on Windows, if the readline extension is enabled.

Using the interactive shell you are able to type PHP code and have it executed directly.

Example #1 Executing code using the interactive shell

$ php -a
Interactive shell

php > echo 5+8;
13
php > function addTwo($n)
php > {
php { return $n + 2;
php { }
php > var_dump(addtwo(2));
int(4)
php >

The interactive shell also features tab completion for functions, constants, class names, variables, static method calls and class constants.

Example #2 Tab completion

Pressing the tab key twice when there are multiple possible completions will result in a list of these completions:

php > strp[TAB][TAB]
strpbrk   strpos    strptime  
php > strp

When there is only one possible completion, pressing tab once will complete the rest on the same line:

php > strpt[TAB]ime(

Completion will also work for names that have been defined during the current interactive shell session:

php > $fooThisIsAReallyLongVariableName = 42;
php > $foo[TAB]ThisIsAReallyLongVariableName

The interactive shell stores your history which can be accessed using the up and down keys. The history is saved in the ~/.php_history file.

The CLI SAPI provides the php.ini settings cli.pager and cli.prompt. The cli.pager setting allows an external program (such as less) to act as a pager for the output instead of being displayed directly on the screen. The cli.prompt setting makes it possible to change the php > prompt.

It is also possible to set php.ini settings in the interactive shell using a shorthand notation.

Example #3 Setting php.ini settings in the interactive shell

The cli.prompt setting:

php > #cli.prompt=hello world :> 
hello world :>

Using backticks it is possible to have PHP code executed in the prompt:

php > #cli.prompt=`echo date('H:i:s');` php > 
15:49:35 php > echo 'hi';
hi
15:49:43 php > sleep(2);
15:49:45 php >

Setting the pager to less:

php > #cli.pager=less
php > phpinfo();
(output displayed in less)
php >

The cli.prompt setting supports a few escape sequences:

**`cli.prompt` escape sequences**
Sequence	Description
`\e`	Used for adding colors to the prompt. An example could be `\e[032m\v \e[031m\b \e[34m\> \e[0m`
`\v`	The PHP version.
`\b`	Indicates which block PHP is in. For instance `/*` to indicate being inside a multi-line comment. The outer scope is denoted by `php`.
`\>`	Indicates the prompt character. By default this is `>`, but changes when the shell is inside an unterminated block or string. Possible characters are: `' " { ( >`

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.

Interactive mode

If the readline extension is not available, prior to PHP 8.1.0, invoking the CLI SAPI with the -a option provided the interactive mode. In this mode, a complete PHP script is supposed to be given via STDIN, and after termination with CTRL +D (POSIX) or CTRL +Z followed by +ENTER (Windows), this script is evaluated. This is basically the same as invoking the CLI SAPI without the -a option.

As of PHP 8.1.0, invoking the CLI SAPI with the -a option fails, if the readline extension is not available.

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User Contributed Notes 7 notes

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177

Ryan P ¶

12 years ago

Interactive Shell and Interactive Mode are not the same thing, despite the similar names and functionality.

If you type 'php -a' and get a response of 'Interactive Shell' followed by a 'php>' prompt, you have interactive shell available (PHP was compiled with readline support). If instead you get a response of 'Interactive mode enabled', you DO NOT have interactive shell available and this article does not apply to you.

You can also check 'php -m' and see if readline is listed in the output - if not, you don't have interactive shell.

Interactive mode is essentially like running php with stdin as the file input. You just type code, and when you're done (Ctrl-D), php executes whatever you typed as if it were a normal PHP (PHTML) file - hence you start in interactive mode with '<?php' in order to execute code.

Interactive shell evaluates every expression as you complete it (with ; or }), reports errors without terminating execution, and supports standard shell functionality via readline (history, tab completion, etc). It's an enhanced version of interactive mode that is ONLY available if you have the required libraries, and is an actual PHP shell that interprets everything you type as PHP code - using '<?php' will cause a parse error.

Finally, if you're running on Windows, you're probably screwed. From what I'm seeing in other comments here, you don't have readline, and without readline there is no interactive shell.

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spencer at aninternetpresence dot net ¶

13 years ago

In Windows, press Enter after your ending PHP tag and then hit Ctrl-Z to denote the end-of-file:



C:\>php -a

Interactive mode enabled



<?php

echo "Hello, world!";

?>

^Z

Hello, world!



You can use the up and down arrows in interactive mode to recall previous code you ran.

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#linuxmint-es ¶

7 years ago

For use interactive mode enabled on GNU/Linux on distros Debian/Ubuntu/LinuxMint you must install "php*-cli" and "php*-readline" packages from official repository.
Example:
 >$sudo aptitude install php5-cli php5-readline

After that you can use interactive mode.
Example:
~ $ php -a
Interactive mode enabled

php >echo "hola mundo!\n";
hola mundo!
php >

I hope somebody help it!

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Anonymous ¶

14 years ago

Just a few more notes to add...

1) Hitting return does literally mean "execute this command".  Semicolon to note end of line is still required.  Meaning, doing the following will produce a parse error:

php > print "test"
php > print "asdf";

Whereas doing the following is just fine:

php > print "test"
php > ."asdf";

2) Fatal errors may eject you from the shell:

name@local:~$ php -a
php > asdf();

Fatal Error: call to undefined function...
name@local:~$

3) User defined functions are not saved in history from shell session to shell session.

4) Should be obvious, but to quit the shell, just type "quit" at the php prompt.

5) In a sense, the shell interaction can be thought of as linearly following a regular php file, except it's live and dynamic.  If you define a function that you've already defined earlier in your current shell, you will receive a fatal "function already defined" error only upon entering that closing bracket.  And, although "including" a toolset of custom functions or a couple of script addon php files is rather handy, should you edit those files and wish to "reinclude" it again, you'll cause a fatal "function x already defined" error.

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John ¶

6 years ago

If you delete your "~/.php_history", you MUST re-create the file manually!

Because after I deleted my history file, "php -a" (interactive mode) never saved any history anymore.

It only started working after I ran "touch ~/.php_history" to create an empty file. From then on, PHP is saving history again!

I thought this was a bit unusual. Normally, applications recreate their history files themselves. But just be aware of the fact that PHP works this way instead, guys and girls! :-)

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Gray ¶

4 years ago

When adding colours, don't forget that PHP uses the same 'readline' as Bash does, so it has the same need to wrap all colour codes in special marker characters.

If you simply add raw colour codes to the prompt, you will notice that long lines no longer get wrapped correctly -- Readline no longer knows how wide the prompt is.

To fix this, you need to start each colour code with an '0x01' byte (aka Ctrl-A aka SOH) and end it with the '0x02' byte (aka Ctrl-B aka STX). There are no escapes for these -- you have to literally put the control characters in your php-cli.ini.

For example:

<?php

// cli.prompt = <SOH>\e[1m<STX> PHP! \> <SOH>\e[m<STX>

echo "cli.prompt = \x01\\e[1m\x02 PHP! \x01\\e[m\x02\n";
?>

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turabgarip at gmail dot com ¶

7 months ago

Note that destructors will not be triggered when exiting interactive shell by any method. (Like CTRL + D, CTRL + Z or CTRL + C).

Since the interactive shell is effectively a continuous runtime, the "end of script" condition is never met for a destructor to run. And exiting the interactive shell is not considered end of script but rather the end of interpreter process. And since the process is dead; it can't run the destructor.

Therefore the only way for a destructor to run is that you remove all the references to the corresponding object. Like:

<?php

class A {
    public function __destructor() {
        // This will never run after ending PHP interactive shell session.
    }
}

$a = new A();

// This is the only way for the destructor to be able to run.
$a = null; // Or;
unset($a);

?>

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