#!/usr/bin/perl -w
use strict;

my @input = ("Exception : CEX",
             "Exception : TEX",
             "abc def ljj");
             
print grep{!/CEX/}grep{/^\s*Exception/}@input;
print "\n";
print grep{/Exception/ && !/CEX/}@input;
print "\n";
__END__
prints:
Exception : TEX
Exception : TEX