$re = '/^(.+)\/(.+)(.cue)$/m';
$str = 'Bryan Adams - 1988 Live! Live! Live!/Bryan Adams - Live! Live! Live!.cue
Bryan Adams - 1993 So Far So Good/Bryan Adams - So Far So Good.cue
Bryan Adams - 2005 Anthology/CD2/Bryan Adams - Anthology CD2.cue
Bryan Adams - 2005 Anthology/CD1/Bryan Adams - Anthology CD1.cue
Bryan Adams - 1988 Hits On Fire/Bryan Adams - Hits On Fire.cue
Bryan Adams - 1997 MTV Unplugged/Bryan Adams - MTV Unplugged.cue';
$subst = "pushd '$1'\nshnsplit -t %n-%t -o flac -f '$2$3' '$2.flac' && rm -f '$2.flac'\npopd\n";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php