install: do not exit with 1 when user asks for help

install.pl

@@ -101,7 +101,7 @@ GetOptions($options, qw(update cron help|h|?))
   or usage();
 
 if ($options->{usage} || (@ARGV != 1 && !$options->{cron})) {
-    usage();
+    usage(0);
 }
 
 check_env();
@@ -235,6 +235,9 @@ sub print_printers {
 }
 
 sub usage {
+    my ($exit_status) = @_;
+    $exit_status //= 1;
+
     print <<END;
 Script for installing faculty printers on Linux via Samba print server.
 usage: $0 {--cron | [--update] <printer-name>}
@@ -248,7 +251,7 @@ END
 
     print_printers();
 
-    exit 1;
+    exit $exit_status;
 }
 
 sub check_python {