config: Substutiton, improve docs

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/README.config b/README.config
index 552843bdb8ba824e6254a649bbc8c54a91f71cf1..a28be23feb97176de3b70a6e64106111567bfb1c 100644 (file)
--- a/README.config
+++ b/README.config
@@ -70,10 +70,11 @@ Exceptional settings:
   ipif
      Command to run to create and communicate with local network
      interface.  Passed to sh -c.  Must speak SLIP on stdin/stdout.
-     The following additional interpolations aare substituted:
+     The following interpolations aare substituted:
                        %(local)s  %(peer)s  %(rnets)s   %(ifname)s
           on server    <vaddr>    <vrelay>  <vnetwork>  <ifname_server>
           on client    <client>   <vaddr>   <vroutes>   <ifname_client>
+     Plus %(mtu)s (and %% to indicate a literal %).
      ["userv root ipif %(local)s,%(peer)s,%(mtu)s,slip %(rnets)s"]
 
      On server: applies to all clients; not looked up in