Fix brown bag bug in previous version.

diff --git a/grading/userprog/prep-disk b/grading/userprog/prep-disk
index f1b766c8614ebebf16d53dc32299d7f8d27bf091..f37a68297b11d2502190f71a51305dc41f5510a2 100755 (executable)
--- a/grading/userprog/prep-disk
+++ b/grading/userprog/prep-disk
@@ -62,6 +62,7 @@ sub put_file {
 sub xsystem {
     my ($expect, $cmd) = @_;
     print "$cmd\n";
+    my ($code) = system ($cmd);
     WIFEXITED ($code) && WEXITSTATUS ($code) == $expect
        or die "command failed\n";
 }