Interactive shell

As of PHP 5.1.0, the CLI SAPI provides an interactive shell using the -a option if PHP is compiled with the --with-readline option.

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;
php > function addTwo($n)
php > {
php { return $n + 2;
php { }
php > var_dump(addtwo(2));
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(

It is also possible doing completion on things that have been defined during the interactive shell session:

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

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


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.


Autoloading is not available if using PHP in CLI interactive mode.

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User Contributed Notes 9 notes

Ryan P
3 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.
spencer at aninternetpresence dot net
4 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

echo "Hello, world!";
Hello, world!

You can use the up and down arrows in interactive mode to recall previous code you ran.
5 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...

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.
5 years ago
It seems the interactive shell cannot be made to work in WIN environments at the moment. 

Using "php://stdin", it shouldn't be too difficult to roll your own.  You can partially mimic the shell by calling this simple script (Note: Window's cmd already has an input history calling feature using the up/down keys, and that functionality will still be available during execution here):


= fopen("php://stdin", "r");
$in = '';
$in != "quit") {
"php> ";
    eval (

Replace 'eval' with code to parse the input string, validate it using is_callable and other variable handling functions, catch fatal errors before they happen, allow line-by-line function defining, etc.  Though Readline is not available in Windows, for more tips and examples for workarounds, see
lee8oi at gmail dot com
3 years ago
I use git-bash in windows to connect to my servers via SSH. When I use the interactive mode via 'php -a' command I have to hit ctrl+d twice to execute the entered code. Example:
(<ctrl+d> denotes hitting ctrl & D)

-bash$ php -a
Interactive mode enabled
echo 'hello world';
?><br />
hello world<br />

Note: this still displays the <br /> tag but without the tag your output would likely be attached to your bash prompt like this:

hello world-bash$
Shane Harter
2 years ago
If you've ever wanted to build your own interactive shell, I released a project recently that makes it insanely easy to build awesome shell apps in PHP. It blends features from Zend2 and Symonfy2 with things like regex routing, state management, etc. Check it out here:
elijah at elijahlynn dot net
1 year ago
Bug #55496 Interactive mode doesn't force a newline before the prompt =>

Fixed on July 24th, 2014 @;a=commit;h=71d3a69425449972f4efdf7228c6f7e49e090755

Until then, this will work:

php -dcli.prompt="\nphp> " -a
alexandrebr at gmail dot com
4 years ago
For those who (just like me) can't get it working, try to press CTRL+D after inserting some commands.

echo "Hello World!\r\n";
Hit CTRL+D here)
Hello World!

This is NOT interactive mode, but may help you.

To have the "-i" available, you'll need the following arguments while compiling PHP:
--with-readline e --with-libedit
4 years ago
When building php on FreeBSD from ports one can add --with-readline option by manually editing the var CONFIGURE_ARGS in Makefile inside the php port directory and proceeding with build as usual.
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