found result:

my $rc = system("grep foobar debug.log");
print "rc = '$rc'\n";

2016/10/31 13:47:21 -5168 [19] Tools.pm 22 Tools.run_test - running te
+st baz with parameters foobar
rc = '0'
[download]

not found result:

my $rc = system("grep blabla debug.log");
print "rc = '$rc'\n";

rc = '256'
[download]