$re = '/^(.*)\.\(.*\)/m';
$str = 'DGL1PLAN_PUT_PFC.FCA#FKS.(CAD17_2013-01-30-21.35.29)
DSN8CC91.DSN8CLTC.(2015-01-14-16.33.06.616783)
DSNAOCLI.DSNCLICS.(UQ40167)
DSNJAR.DSNX9DIJ.(UK81051)';
$subst = "$1";
$result = preg_replace($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