Add missing documentation for error_banner

Author: cyrilst

cmd/sshproxyctl/sshproxyctl.go

@@ -486,7 +486,7 @@ The commands are:
   hosts         show hosts stored in etcd
   users         show users stored in etcd
   groups        show groups stored in etcd
-  error_banner  show error banner stored in etcd and in configuration
+  error_banner  show error banners stored in etcd and in configuration
 
 The options are:
 `, os.Args[0])

doc/sshproxyctl.txt

@@ -54,6 +54,14 @@ COMMANDS
 	Forget a host in etcd. The default port is 22. Remember that if this
 	host is used, it will appear back in the list.
 
+*error_banner [-expire] MESSAGE*::
+	Set the error banner in etcd. Removes the error banner in etcd if
+	'MESSAGE' is absent. 'MESSAGE' can be multiline. The error banner is
+	displayed to the client when no backend can be reached (more
+	precisely, when all backends are either down or disabled in etcd).
+	'-expire' sets the expiration date of this error banner. Format:
+	'YYYY-MM-DD[ HH:MM[:SS]]'
+
 *show [-all] [-csv|-json] connections*::
 	Show users connections in etcd. Without '-all' only one entry per user
 	is displayed with the number of her/his connections. If '-all' is
@@ -71,6 +79,9 @@ COMMANDS
 	group is displayed. If '-all' is specified, groups are splitted by
 	services.
 
+*show error_banner*::
+	Show error banners stored in etcd and in configuration.
+
 
 FILES
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