my $diff1 = system("sh diff.sh");
my $diff2 = system("sh diff1.sh");

##</code><code>##

a=diff aaa ccc

##</code><code>##

b=diff aaa bbb

##</code><code>##

diff aaa bbb
a=$?
# do something else with $a
exit $a

##</code><code>##

diff aaa bbb

##</code><code>##

  my $diff1 = system("diff aaa ccc >/dev/null 2>&1");
  my $diff2 = system("diff aaa bbb >/dev/null 2>&1");