Knowing if php script is submitted to an output redirection

Question

I have a php script which is run in the terminal and it returns a number the number is human-friendly formated so :

php script.php

will for example output: 1 020 536

But sometimes we need this script to output the number as a computer-friendly version so in my case :

1020536

Is it possible to detect directly from the php script if it's called directly or in the following ways :

echo $(php script.php)

and

php script.php | cat

The both version should output the number non formated.

Is that possible ?

Thanks in advance !

Answer 1

You can do that with posix-isatty. Here is an example;

in your script.php you can implement;

<?php

if ( !posix_isatty(STDOUT) ) {
    fwrite(STDOUT, "You piped this script to another command");
    exit(2);
}
fwrite(STDOUT, "Called directly");

exit(0);

?>

Update: Just for the incomers:

posix_isatty helps you to detect if script output piped to elsewhere or not. In case above, posix_isatty(STDOUT) means, your php script outputs to terminal. If you pipe your php script like php script | cat, posix_isatty(STDOUT) will be false. Because, you have redirected output of your script to cat as input. In other words, you redirected your script output to place that is not an terminal.