1 files changed, 4 insertions, 2 deletions

diff --git a/tail.c b/tail.c
index 315eee188..321c5c4b2 100644
--- a/tail.c
+++ b/tail.c
@@ -368,8 +368,10 @@ extern int tail_main(int argc, char **argv)
                         case 'h':
                                 usage(tail_usage);
                         default:
-                                fprintf(stderr, "tail: invalid option -- %c\n", opt);
-                                usage(tail_usage);
+                                if ((n_units = atoi(&argv[i][1])) < 1) {
+                                        fprintf(stderr, "tail: invalid option -- %c\n", opt);
+                                        usage(tail_usage);
+                                }
                         }
                 } else {
                         break;