$PRE    = '\[\s*(';
$VALID1 = '[-a-zA-Z0-9_.*\s]';
$PST    = ')\s*\]';
while (<DATA>)
{
    print "yep\n"  if /$PRE($VALID1+)$PST/;
}


__DATA__
[TEST \n DATA]\n
[ TEST DATA ]\n