Execute a command and pipe its output to stdout (echo it) as it's recieved, rather than wait for the command to finish executing

execAndPipeOutput.php

<?php

function execAndPipeOutput($cmd)
{
    echo PHP_EOL;
    $proc = proc_open($cmd, [['pipe','r'],['pipe','w'],['pipe','w']], $pipes);
    while(($line = fgets($pipes[1])) !== false) {
        fwrite(STDOUT, $line);
    }
    while(($line = fgets($pipes[2])) !== false) {
        fwrite(STDERR, $line);
    }
    fclose($pipes[0]);
    fclose($pipes[1]);
    fclose($pipes[2]);
    proc_close($proc);
    echo PHP_EOL;
}