<?php
$myfile = 'a,2014-10-05 19:00:40,
b,2014-10-05 19:00:31,';
$name = 'a';
if(preg_match("/$name\,(.*),/", $myfile, $matches)) {
//$results = preg_replace("/$name.*\,/", $txt, $myfile);
}
echo $matches[1];
PD9waHAKCiRteWZpbGUgPSAnYSwyMDE0LTEwLTA1IDE5OjAwOjQwLAoKYiwyMDE0LTEwLTA1IDE5OjAwOjMxLCc7CgokbmFtZSA9ICdhJzsKCmlmKHByZWdfbWF0Y2goIi8kbmFtZVwsKC4qKSwvIiwgJG15ZmlsZSwgJG1hdGNoZXMpKQp7CiAgIC8vJHJlc3VsdHMgPSBwcmVnX3JlcGxhY2UoIi8kbmFtZS4qXCwvIiwgJHR4dCwgJG15ZmlsZSk7Cn0KCmVjaG8gJG1hdGNoZXNbMV07