.TH PATCH 1
.SH NAME
patch \- simple patch creation and tracking system
.SH SYNOPSIS
.B patch/create
.I name
.I email
.I files ...
[
.B < 
.I description
]
.PP
.B patch/list
[
.I name ...
]
.PP
.B patch/diff
.I name
.PP
.B patch/apply
.I name
.PP
.B patch/undo
.I name
.PP
.B patch/note
.I name 
[
.B <
.I note
]
.SH DESCRIPTION
These scripts are a simple patch submission and tracking system
used to propose additions or changes to Plan 9.
Each patch has a 
.I name
(lowercase letters, numbers, dash, dot, and underscore only)
and is stored in
.BI /n/sources/patch/ name \fR.
.PP
.I Patch/create
creates a new patch consisting of the changes to
the listed files, reading
a description of the patch from standard input.
The
.I email
address, if not
.LR - ,
will be sent notification messages when the patch is applied
or commented on.
.PP
.I Patch/list
displays information about the named patches,
or all currently pending patches if none are specified.
.PP
.I Patch/diff
shows a patch as diffs between the original
source files and the patched source files.
.PP
.I Patch/apply
applies the patch to the current source tree.
It is intended to be run by the Plan 9 developers 
with emelie as their root file system.
If the source has changed since the patch was
created,
.I apply
will report the conflict and not change any files.
Before changing any files,
.I patch/apply
makes backup copies of the current source tree's
files.  The backups are stored in the patch directory.
.PP
.I Patch/undo
will copy the backups saved by
.I patch/apply
back into the source tree.
It will not restore a backup if the file
being replaced is not byte-identical to the one
created by 
.I patch/apply.
.SH EXAMPLES
.PP
Propose a change to
.IR pwd ,
which you have modified locally:
.EX
% patch/create pwd-errors user@host.dom /sys/src/cmd/pwd.c
Fix pwd to print errors to fd 2 rather than 1.
^D
% 
.EE
.PP
Then the developers at Bell Labs run
.EX
patch/diff pwd-errors
.EE
to inspect the change (possibly viewing
.B /n/sources/patch/pwd-errors/pwd.c
to see the larger context).
To make the change, they run
.EX
patch/apply pwd-errors
.EE
Otherwise they run
.EX
% patch/note pwd-errors
Pwd should definitely print errors to fd 1 because ...
^D
% 
.EE
to add a note to the 
.B /n/sources/pwd-errors/notes
file.
.SH FILES
.B /n/sources/patch
.SH SOURCE
.B /rc/bin/patch
.SH SEE ALSO
.IR diff (1)