nmss_/var/scripts # cat test.pl
#!/usr/bin/perl -w

use NETWORK::SNMP;
use NETWORK::Discovery;

print "$commstring\n";

nmss_/var/scripts # ./test.pl
not_real_community_string

nmss_/var/scripts # cat test2.pl
#!/usr/bin/perl -w

use NETWORK::Discovery;
use NETWORK::SNMP;

print "$commstring\n";

nmss_/var/scripts # ./test2.pl
Name "main::commstring" used only once: possible typo at ./test2.pl line 6.
Use of uninitialized value in concatenation (.) at ./test2.pl line 6.