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

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

__END__
prints:
Exception : TEX
Exception : TEX
Exception : TEX