posix_isatty

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

posix_isattyDetermine if a file descriptor is an interactive terminal

说明

posix_isatty ( resource|int $file_descriptor ) : bool

Determines if the file descriptor file_descriptor refers to a valid terminal type device.

参数

fd

The file descriptor, which is expected to be either a file resource or an int. An int will be assumed to be a file descriptor that can be passed directly to the underlying system call.

In almost all cases, you will want to provide a file resource.

返回值

Returns true if file_descriptor is an open descriptor connected to a terminal and false otherwise.

参见

User Contributed Notes

KEINOS 08-Jan-2021 10:34
It's quite complicated to understand its movements. But it determines if the file_descriptor is open AND connected to a terminal.

Thus, while receiving data from the STDIN, for example, it will return false.

This move is useful to optionally pipe STDIN to a PHP script, to avoid hanging when nothing is from STDIN.

<?php

// Simply echoes the contents from STDIN if any
// and "no stdin" if not.
echo (posix_isatty(STDIN)) ? 'no stdin' . PHP_EOL : file_get_contents('php://stdin');
?>
hfuecks at phppatterns dot com 07-May-2004 02:12
Can be useful to determine whether output is being piped elsewhere, for PHP shell scripts, for example;

#!/usr/local/bin/php
<?php
if ( !posix_isatty(STDOUT) ) {
   
fwrite(STDOUT, "Invalid TTY\n");
    exit(
2);
}
fwrite(STDOUT, "Enter you name\n");
$name = fgets(STDIN);
fwrite(STDOUT,"Hello $name\n");
exit(
0);
?>

If this script is like:

script.php > outfile

outfile will contain "Invalid TTY"