diff --git a/nixos/modules/services/network-filesystems/tahoe.nix b/nixos/modules/services/network-filesystems/tahoe.nix
index f70fbcc49751..26c64f5f72fe 100644
--- a/nixos/modules/services/network-filesystems/tahoe.nix
+++ b/nixos/modules/services/network-filesystems/tahoe.nix
@@ -243,7 +243,7 @@ in
             preStart = ''
               if [ ! -d ${lib.escapeShellArg nodedir} ]; then
                 mkdir -p /var/db/tahoe-lafs
-                tahoe create-introducer "${lib.escapeShellArg nodedir}
+                tahoe create-introducer "${lib.escapeShellArg nodedir}"
               fi
 
               # Tahoe has created a predefined tahoe.cfg which we must now