Example of using php and libevent to processs a file at the command line by pipping it to the file.

gistfile1.txt

a,b,c
d,e,f
---
<?php
global $writer;

$fileName = "./new.csv";
unlink($fileName);
$writer = fopen($fileName, "a+");

function parseInput($fd, $events, $arg)
{
    global $writer;
    static $max_requests = 0;

    if ($max_requests == 2) {
        fclose($writer);
        event_base_loopexit($arg[1]);
    }

    // print the line
    $str = fgets($fd);
    if (empty($str)) {
        $max_requests++;
        return;
    }
    $max_requests = 0;

    $str = strrev($str);
    $a = str_getcsv($str);

    fputcsv($writer, $a);
}

// create base and event
$base = event_base_new();
$event = event_new();

$fd = STDIN;

// set event flags
event_set($event, $fd, EV_READ | EV_PERSIST, "parseInput", array($event, $base));
// set event base
event_base_set($event, $base);

// enable event
event_add($event);
// start event loop
event_base_loop($base);