1 files changed, 4 insertions, 4 deletions
diff --git a/user/grep.c b/user/grep.c
index 5e1f2c0..43406b8 100644
--- a/user/grep.c
+++ b/user/grep.c
@@ -41,24 +41,24 @@ main(int argc, char *argv[])
 
   if(argc <= 1){
     fprintf(2, "usage: grep pattern [file ...]\n");
-    exit();
+    exit(-1);
   }
   pattern = argv[1];
 
   if(argc <= 2){
     grep(pattern, 0);
-    exit();
+    exit(0);
   }
 
   for(i = 2; i < argc; i++){
     if((fd = open(argv[i], 0)) < 0){
       printf("grep: cannot open %s\n", argv[i]);
-      exit();
+      exit(-1);
     }
     grep(pattern, fd);
     close(fd);
   }
-  exit();
+  exit(0);
 }
 
 // Regexp matcher from Kernighan & Pike,