nghttpx: Update doc

src/shrpx.cc

@@ -998,7 +998,7 @@ Options:
   The options are categorized into several groups.
 
 Connections:
-  -b, --backend=<HOST>,<PORT>[;<PATTERN>[:...]]
+  -b, --backend=(<HOST>,<PORT>|unix:<PATH>)[;<PATTERN>[:...]]
               Set  backend  host  and   port.   The  multiple  backend
               addresses are  accepted by repeating this  option.  UNIX
               domain socket  can be  specified by prefixing  path name
@@ -1009,27 +1009,27 @@ Connections:
               -p  is  used,  <PATTERN>s   are  ignored.   The  pattern
               matching  is closely  designed to  ServeMux in  net/http
               package of Go  programming language.  <PATTERN> consists
-              of path, host + path or just host.  The path must starts
-              with  "/".  If  it  ends  with "/",  it  matches to  the
-              request path whose prefix is the path.  To deal with the
-              request to the directory without trailing slash, pattern
-              which ends with "/" also  matches the path if pattern ==
-              path + "/" (e.g.,  pattern "/foo/" matches path "/foo").
-              If it  does not  end with "/",  it performs  exact match
-              against the request path.  If host is given, it performs
-              exact match against the request  host.  If host alone is
-              given, "/"  is appended  to it, so  that it  matches all
-              paths  under the  host  (e.g., specifying  "nghttp2.org"
-              equals to "nghttp2.org/").
-
-              Patterns  with  host  take  precedence  over  path  only
-              patterns.   Then, longer  patterns take  precedence over
+              of path, host + path or  just host.  The path must start
+              with "/".  If  it ends with "/", it  matches all request
+              path in  its subtree.  To  deal with the request  to the
+              directory without  trailing slash,  the path  which ends
+              with "/" also matches the  request path which only lacks
+              trailing '/'  (e.g., path  "/foo/" matches  request path
+              "/foo").  If it does not end with "/", it performs exact
+              match against  the request path.   If host is  given, it
+              performs exact match against  the request host.  If host
+              alone  is given,  "/"  is  appended to  it,  so that  it
+              matches  all   request  paths  under  the   host  (e.g.,
+              specifying "nghttp2.org" equals to "nghttp2.org/").
+
+              Patterns with  host take  precedence over  patterns with
+              just path.   Then, longer patterns take  precedence over
               shorter  ones,  breaking  a  tie by  the  order  of  the
               appearance in the configuration.
 
               If <PATTERN> is  omitted, "/" is used  as pattern, which
-              matches  all paths  (catch-all pattern).   The catch-all
-              backend must be given.
+              matches  all  request  paths (catch-all  pattern).   The
+              catch-all backend must be given.
 
               When doing  a match, nghttpx made  some normalization to
               pattern, request host and path.  For host part, they are
@@ -1047,15 +1047,18 @@ Connections:
               them            by           ":".             Specifying
               -b'127.0.0.1,8080;nghttp2.org:www.nghttp2.org'  has  the
               same  effect  to specify  -b'127.0.0.1,8080;nghttp2.org'
-              and -b'127.0.0.1,8080:www.nghttp2.org'.
+              and -b'127.0.0.1,8080;www.nghttp2.org'.
 
               The backend addresses sharing same <PATTERN> are grouped
-              together forming  load balancing  group.  Since  ";" and
-              ":" are  used as  delimiter, <PATTERN> must  not contain
-              these characters.
+              together forming  load balancing  group.
+
+              Since ";" and ":" are  used as delimiter, <PATTERN> must
+              not  contain these  characters.  Since  ";" has  special
+              meaning in shell, the option value must be quoted.
+
               Default: )" << DEFAULT_DOWNSTREAM_HOST << ","
       << DEFAULT_DOWNSTREAM_PORT << R"(
-  -f, --frontend=<HOST>,<PORT>
+  -f, --frontend=(<HOST>,<PORT>|unix:<PATH>)
               Set  frontend  host and  port.   If  <HOST> is  '*',  it
               assumes  all addresses  including  both  IPv4 and  IPv6.
               UNIX domain  socket can  be specified by  prefixing path