$re = '/\<(\d+)\>(\w+[\d\s\:]+\S+\s\S+\s(\d+)\s(\d+)\s(\d+)\s([\d\:\-\.\+\s]{0,30})\s+\d+)\s+(\d+)\s+(\S+)\s+(\S+\:.*?)(.*)/m';
$str = '<180>May 19 17:54:27 ise121 CISE_Internal_Operations_Diagnostics 0000046406 2 0 2015-05-19 17:54:27.930 +05:30 0000290168 34126 WARN System-Management: Remote syslog target is unavailable';
$subst = "";
$result = preg_replace($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