diff --git a/goaljobs.ml b/goaljobs.ml
index fcbcf236ca5d482914c9ef516490b5c68e013deb..4024b6da999770be1dc4c56fcc60853c95e2f541 100644
--- a/goaljobs.ml
+++ b/goaljobs.ml
@@ -216,7 +216,7 @@ let url_exists url =
     goal_failed msg
 
 let file_contains_string filename str =
-  let cmd = sprintf "grep -q %s %s" (quote str) (quote filename) in
+  let cmd = sprintf "grep -q -F %s %s" (quote str) (quote filename) in
   match Sys.command cmd with
   | 0 -> true
   | 1 -> false