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readline

(PHP 4, PHP 5, PHP 7, PHP 8)

readline — Reads a line

Description

readline(?string $prompt = null): string|false

Reads a single line from the user. You must add this line to the history yourself using readline_add_history().

Parameters

prompt: You may specify a string with which to prompt the user.

Return Values

Returns a single string from the user. The line returned has the ending newline removed. If there is no more data to read, then false is returned.

Examples

Example #1 readline() Example


<?php
//get 3 commands from user
for ($i=0; $i < 3; $i++) {
        $line = readline("Command: ");
        readline_add_history($line);
}

//dump history
print_r(readline_list_history());

//dump variables
print_r(readline_info());
?>

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User Contributed Notes 13 notes

down

Antony Penn ¶

1 year ago


Christian's code works well, but if you want to be able to hide the user input and not echo it to screen, you need to add -s to the read command. The code below is an expanded function that allows an optional prompt and optional hiding of the input:

function read_password($prompt=null, $hide=false)
{
    if($prompt) print $prompt;
    $s = ($hide) ? '-s' : '';
    $f=popen("read $s; echo \$REPLY","r");
    $input=fgets($f,100);
    pclose($f);
    if($hide) print "\n";
    return $input;
}

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turdsurfer ¶

4 years ago


If your CLI script accepts input from STDIN and you also want it to prompt for a password (e.g. as mysql client does), then readline() won't work for you. 
What you need to do is read from the terminal device as shown below.

function readline_terminal($prompt = '') {
    $prompt && print $prompt;
    $terminal_device = '/dev/tty';
    $h = fopen($terminal_device, 'r');
    if ($h === false) {
        #throw new RuntimeException("Failed to open terminal device $terminal_device");
        return false; # probably not running in a terminal.
    }
    $line = rtrim(fgets($h),"\r\n");
    fclose($h);
    return $line;
}
$pass = readline_terminal('Password: ');

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rojaro at gmail dot com ¶

12 years ago


Note that readline() will return boolean "false" when the user presses CTRL+D.

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taneli at crasman dot fi ¶

12 years ago


If you want to prefill the prompt with something when using readline, this worked for me:



<?php

  function readline_callback($ret)

  {

    global $prompt_answer, $prompt_finished;

    $prompt_answer = $ret;

    $prompt_finished = TRUE;

    readline_callback_handler_remove();

  }



  readline_callback_handler_install('Enter some text> ',

                                    'readline_callback');



  $prefill = 'foobar';

  for ($i = 0; $i < strlen($prefill); $i++)

  {

    readline_info('pending_input', substr($prefill, $i, 1));

    readline_callback_read_char();

  }



  $prompt_finished = FALSE;

  $prompt_answer = FALSE;

  while (!$prompt_finished)

    readline_callback_read_char();

  echo 'You wrote: ' . $prompt_answer . "\n";

?>

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Anonymous ¶

10 years ago


The readline library is not available on Windows.

<?php
if (PHP_OS == 'WINNT') {
  echo '$ ';
  $line = stream_get_line(STDIN, 1024, PHP_EOL);
} else {
  $line = readline('$ ');
}
?>

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cox at idecnet dot com ¶

19 years ago


In CGI mode be sure to call:

ob_implicit_flush(true);

at the top of your script if you want to be able to output data before and after the prompt.

-- Tomas V.V.Cox

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soletan at toxa dot de ¶

15 years ago


To haukew at gmail dot com: 

readline provides more features than reading a single line of input ... your example misses line editing and history. If you don't need that, use something as simple as this:

function readline( $prompt = '' )
{
    echo $prompt;
    return rtrim( fgets( STDIN ), "\n" );
}

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christian at gaeking dot de ¶

17 years ago


A workaround if readline is not compiled into php, because for example the command is only needed within an installation routine. It works as follows under Linux:

$f=popen("read; echo \$REPLY","r");
$input=fgets($f,100);
pclose($f);        
echo "Entered: $input\n";

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-1

thflori ¶

3 years ago


If you want to block remove previous text and wonder that an empty string does not work: the workaround is to use an space with cursor left:

<?php

echo "> ";
readline(" \e[D");

?>

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-2

sean ¶

12 years ago


I wanted a function that would timeout if readline was waiting too long... this works on php CLI on linux:



<?php



function readline_timeout($sec, $def)

{

    return trim(shell_exec('bash -c ' .

        escapeshellarg('phprlto=' .

            escapeshellarg($def) . ';' .

            'read -t ' . ((int)$sec) . ' phprlto;' .

            'echo "$phprlto"')));

}



?>



Just call readline_timeout(5, 'whatever') to either read something from stdin, or timeout in 5 seconds and default to 'whatever'.  I tried just using shell_exec without relying on bash -c, but that didn't work for me, so I had to go the round about way.

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-2

Anonymous ¶

4 years ago


a few observations....

I use Cygwin PHP v7 and readline is available. The readline_list_history() function though is not defined.

A prompt with escape sequences are sanitized, so use something like:

<?php
    echo("\e[0m\e[34mPromt>\e[0m");
    $inp = readline(' ');
?>

I have not fully documented it, but I see that sometimes strings beginning with punctuation characters do not make it into the history with readline_add_history(). They also sometimes clear the prompt string.

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-3

Ixios ¶

3 years ago


Works under windows, and under php 7.2.0 :

$arr = [];

for ($i=0; $i < 3; $i++) {
        $arr[$i] = readline("Commande : ");
}

// Output
print_r($arr);

----------

Output:

Commande : 658
Commande : 965
Commande : 478
Array
(
    [0] => 658
    [1] => 965
    [2] => 478
)

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-5

roddric dot kasen at gmail dot com ¶

5 years ago


<?php

class ConsoleQuestion
{

    function readline()
    {
        return rtrim(fgets(STDIN));
    }
}

//Example1
$line = new ConsoleQuestion();
$prompt = "What Is Your Name: ";
echo $prompt;
$answer = $line->readline();
echo "You Entered: " . $answer;

//Example2 (comment Ex1 then uncomment Ex2)
/*$prompt = "What Is Your Name: ";
echo $prompt;
$answer =  "You Entered: " . rtrim( fgets( STDIN ));
echo $answer;*/

?>

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