add Local documentation

Reference: /n/atom/patch/applied/plumbman
Date: Mon Feb 10 16:16:40 CET 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/man/1/plumb	Mon Feb 10 16:16:28 2014
+++ /sys/man/1/plumb	Mon Feb 10 16:16:28 2014
@@ -1,6 +1,6 @@
 .TH PLUMB 1
 .SH NAME
-plumb \- send message to plumber
+plumb, Local \- send message to plumber
 .SH SYNOPSIS
 .B plumb
 [
@@ -25,6 +25,9 @@
 .B -i
 |
 .I data...
+.br
+Local
+.I cmd...
 .SH DESCRIPTION
 The
 .I plumb
@@ -75,6 +78,12 @@
 will add an
 .B action=showdata
 attribute to the message.
+.PP
+.I Local
+runs its argument, which is assumed to be idempotent, in the
+plumber's namespace using
+.L Local 
+as well as the namespace of the caller.
 .SH FILES
 .TF /usr/$user/lib/plumbing
 .TP
@@ -86,6 +95,8 @@
 .IR plumber (4).
 .SH SOURCE
 .B /sys/src/cmd/plumb
+.br
+.B /rc/bin/Local
 .SH "SEE ALSO"
 .IR plumb (2),
 .IR plumber (4),