Document :shell-command in `make-network-process'

* doc/lispref/processes.texi (Network): Document :shell-command.

* lisp/net/network-stream.el (open-network-stream): Document
the :shell-command parameter (bug#20651).

2 files changed, 12 insertions, 0 deletions

diff --git a/doc/lispref/processes.texi b/doc/lispref/processes.texi
index 014a0aed913..58e04a311a1 100644
--- a/doc/lispref/processes.texi
+++ b/doc/lispref/processes.texi
@@ -2414,6 +2414,14 @@ If non-@code{nil}, the host's capability string.
 The connection type: @samp{plain} or @samp{tls}.
 @end table
 
+@item :shell-command @var{string-or-nil}
+If the connection @code{type} is @code{shell}, this parameter will be
+interpreted as a format-spec string that will be executed to make the
+connection.  The specs available are @samp{%s} for the host name and
+@samp{%p} for the port number.  For instance, if you want to first ssh
+to @samp{gateway} before making a plain connection, then this
+parameter could be something like @samp{ssh gateway nc %s %p}.
+
 @end table
 
 @end defun
diff --git a/lisp/net/network-stream.el b/lisp/net/network-stream.el
index 93e1bae5fc2..bf60eee673c 100644
--- a/lisp/net/network-stream.el
+++ b/lisp/net/network-stream.el
@@ -139,6 +139,10 @@ a greeting from the server.
 :nowait, if non-nil, says the connection should be made
 asynchronously, if possible.
 
+:shell-command is a format-spec string that can be used if :type
+is `shell'.  It has two specs, %s for host and %p for port
+number.  Example: \"ssh gateway nc %s %p\".
+
 :tls-parameters is a list that should be supplied if you're
 opening a TLS connection.  The first element is the TLS
 type (either `gnutls-x509pki' or `gnutls-anon'), and the