1 files changed, 4 insertions, 2 deletions

diff --git a/tr.c b/tr.c
index 48cdd47bd..5a8116db0 100644
--- a/tr.c
+++ b/tr.c
@@ -187,10 +187,12 @@ extern int tr_main(int argc, char **argv)
                 expand(argv[index++], input);
                 if (com_fl)
                         complement(input);
-                if (argv[index] != NULL)
+                if (argv[index] != NULL) {
+                        if (*argv[index] == '\0')
+                                fatalError("tr: STRING2 cannot be empty\n");
                         expand(argv[index], output);
-                if (argv[index] != NULL)
                         map(input, output);
+                }
                 for (ptr = input; *ptr; ptr++)
                         invec[*ptr] = TRUE;
                 for (ptr = output; *ptr; ptr++)