diff --git a/man7/user_namespaces.7 b/man7/user_namespaces.7
index 22fda19d9..964930958 100644
--- a/man7/user_namespaces.7
+++ b/man7/user_namespaces.7
@@ -551,7 +551,8 @@ otherwise all of the following restrictions apply:
 The data written to
 .I uid_map
 .RI ( gid_map )
-consists of a single line that maps the writing process's effective user ID
+must consist of a single line that maps
+the writing process's effective user ID
 (group ID) in the parent user namespace to a user ID (group ID)
 in the user namespace.
 .IP +