PHP: Shell interattiva

Shell interattiva

La CLI SAPI fornisce una shell interattiva quando si usa l'opzione -a se PHP è compilato con l'opzione --with-readline. Da PHP 7.1.0 la shell interattiva è anche disponibile su Windows, se l'estensione readline è abilitata.

Utilizzando la shell interattiva si può digitare codice PHP ed eseguirlo direttamente.

Example #1 Esecuzione di codice con la shell interattiva

$ 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 >

La shell interattiva fornisce anche il completamento automatic (tab completion) di funzioni, costanti, nomi di classe, variabili, metodi statici e costanti di classe.

Example #2 Tab completion

Premere il tasto Tab due volte quando ci sono molteplici possibilità di completamento visualizzerà un elenco di questi elementi:

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

Quando esiste un solo completamento possibile, una pressione sul tasto tab completa il resto della linea:

php > strpt[TAB]ime(

Il completamento funziona anche per il nomi che sono stati definiti durante la sessione corrente della shell:

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

La shell interattiva archiva lo storico che può essere consultato usando i tasti su e giù. Lo storico è salvato nel file ~/.php_history.

La CLI SAPI mette a disposizione le impostazioni php.ini cli.pager e cli.prompt. Il valore cli.pager permette ad un programma esterno (come less) di agire come un paginatore per l'output invece di visualizzarlo direttamente sullo schermo. Il parametro cli.prompt permette di cambiare il prompt php >.

È anche possibile impostare le impostazioni di php.ini nella shell interattiva utilizzando una notazione abbreviata.

Example #3 Impostare i valori del php.ini nella shell interattiva

Il parametro cli.prompt:

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

Utilizzando gli apici inversi è possibile eseguire codice PHP nel 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 >

Impostazione del paginatore a less:

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

Il parametro cli.prompt ammette alcune sequenze di escape:

**Sequenze di escape di `cli.prompt`**
Sequenza	Descriztione
`\e`	Usata per aggiungere colori al prompt. Un esempio può essere `\e[032m\v \e[031m\b \e[34m\> \e[0m`
`\v`	La versione del PHP.
`\b`	Indica in che tipo di blocco si trova PHP. Per esempio `/*` indica che si è in un commento multilinea. L'ambito esterno è indicato da `php`.
`\>`	Indica il caratter di prompt. L'impostazione predefinita è `>`, ma cambia quando la shell è all'interno di un blocco non terminato o una stringa. I caratteri utilizzabili sono: `' " { ( >`

Nota:
I file inclusi con auto_prepend_file e auto_append_file sono analizzati in questa modialità ma con qualche restrizione - es. le funzioni devono essere definite prima della chiamata.

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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.

down

#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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