1 files changed, 2 insertions, 1 deletions

diff --git a/chpst.c b/chpst.c
index 8de213f..1c3073f 100644
--- a/chpst.c
+++ b/chpst.c
@@ -309,7 +309,8 @@ int main(int argc, char **argv) {
     case 'n':
       switch (*optarg) {
         case '-':
-          if (optarg[scan_ulong(++optarg, &ul)]) usage();
+          ++optarg;
+          if (optarg[scan_ulong(optarg, &ul)]) usage();
           nicelvl =ul;
           nicelvl *=-1;
           break;