diff --git a/.bashrc b/.bashrc
index be55388..97c5b36 100644
--- a/.bashrc
+++ b/.bashrc
@@ -31,7 +31,7 @@ complete -cf boas
 
 # Random string (passwords)
 randstr() {
-	tr -cd [:graph:] </dev/urandom | head -c ${1:-256}
+	tr -cd '[:graph:]' </dev/urandom | head -c ${1:-256}
 }
 
 # Get CPU usage