diff --git a/utils/tweak.in b/utils/tweak.in
--- a/utils/tweak.in
+++ b/utils/tweak.in
@@ -1,8 +1,8 @@
 #!/bin/bash
 # Manipulate options in a .config file from the command line
 
-# If no prefix forced, use the default CONFIG_
-CONFIG_="${CONFIG_-CONFIG_}"
+# If no prefix forced, use the default @CONFIG_@
+CONFIG_="${CONFIG_-@CONFIG_@}"
 
 usage() {
 	cat >&2 <<EOL
@@ -39,7 +39,7 @@
 By default, config will upper-case the given symbol. Use --keep-case to keep
 the case of all following symbols unchanged.
 
-config uses 'CONFIG_' as the default symbol prefix. Set the environment
+config uses '@CONFIG_@' as the default symbol prefix. Set the environment
 variable CONFIG_ to the prefix to use. Eg.: CONFIG_="FOO_" config ...
 EOL
 	exit 1