$re = '/[\r\n]+/m';
$str = '#EXTINF:-1 tvg-name="seedocs" tvg-logo="RT",RT
http://rt.ashttp14.visionip.tv/live/rt-global-live-HD/playlist.m3u8
#EXTINF:-1 tvg-name="hsn" tvg-logo="hsn",HSN TV
rtsp://hsn.mpl.miisolutions.net:1935/hsn-live01/_definst_/mp4:420p500kB31
#EXTINF:-1 tvg-name="us" tvg-logo="us",USTwit
http://bglive-a.bitgravity.com/twit/live/high
#EXTINF:-1 tvg-name="ALJAZEERA" tvg-logo="aljazeera",Aljazeera
rtmp://aljazeeraflashlivefs.fplive.net/aljazeeraflashlive-live/aljazeera_eng_high
#EXTINF:-1 tvg-name="bbc" tvg-logo="bbc",BBC World News
#EXTINF:-1 tvg-name="vevo" tvg-logo="vevo",Vevo
http://vevoplaylist-live.hls.adaptive.level3.net/vevo/ch1/06/prog_index.m3u8
#EXTINF:-1 tvg-name="vevo2" tvg-logo="vevo2",Vevo 2
http://vevoplaylist-live.hls.adaptive.level3.net/vevo/ch3/06/prog_index.m3u8
#EXTINF:-1 tvg-name="1HD" tvg-logo="1HD",1HD
rtmp://109.239.142.62/live/livestream3';
$subst = "\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