next;
                }
                if ($arg eq '-g' || $arg eq '--gui') {
-                       my $tool = Git::command_oneline('config',
-                                                       'diff.guitool');
-                       if (length($tool)) {
-                               $ENV{GIT_DIFF_TOOL} = $tool;
-                       }
+                       eval {
+                               my $tool = Git::command_oneline('config',
+                                                               'diff.guitool');
+                               if (length($tool)) {
+                                       $ENV{GIT_DIFF_TOOL} = $tool;
+                               }
+                       };
                        next;
                }
                if ($arg eq '-y' || $arg eq '--no-prompt') {