使用和制作patch文件

发表时间: 2007-2-13 20:57    作者: superuser    来源: 迷茫人

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• superuser (2007-2-13 21:12:26)

  Patching (very) Mini Howto
  Introduction

  This very short document is a slightly lengthened version of an email I wrote in 2003 on the subject of patches, I’ve put it here in case it could be useful to anyone else.
  The Howto

  cd into the directory containing the sources you want to patch:

  CODE:

  $ cd madwifiThen you need to pipe the patch file into the program ‘patch’, like this:

  CODE:

  $ cat /path/to/patch/patch.diff | patch -p1The processs for applying gzipped or bzipped patches is almost identical, only you use a modified version of ‘cat’ which can handle the compression thats been used e.g:

  CODE:

  $ bzcat /path/to/patch/patch.bz2 | patch -p1for bzips, or

  CODE:

  $ zcat /path/to/patch/patch.gz2 | patch -p1for the (more common) gzips.

  Another way which might interest some people (which I’ve just descovered) is to do things the other way around, in this way you can do it without running cat:

  CODE:

  $ patch -p1 < patchI’m not exactly sure how to do this with zipped patches just yet however, my experiments would lead me to belive that its more complex than most of what’s above.

  The option -p1 tells the patch program to remove 1 layer of all the filenames from the input, you do this because normally the person who made the patch is one directory closer to / than you. The best way to explain this is too look at the content of a patch (this is part of the wireless extensions patch):

  CODE:

  diff -u -p linux/include/linux/wireless.15.h linux/include/linux/wireless.h
--- linux/include/linux/wireless.15.h   Fri Jan 10 16:55:07 2003
+++ linux/include/linux/wireless.h  Wed Apr  2 16:33:31 2003The lines mention “linux/include/[…]”, now if you have more than one set of kernel sources on your system, then the one you want to patch will not necessarily be in as directory called ‘linux’, the -p1 option would strip the linux from the filename and just leave:

  CODE:

  diff -u -p include/linux/wireless.15.h include/linux/wireless.h
--- include/linux/wireless.15.h   Fri Jan 10 16:55:07 2003
+++ include/linux/wireless.h  Wed Apr  2 16:33:31 2003From the above discussion, it should be fairly easy to see that patch strips from the left hand side, and removes n slashes. Where n is the number the ‘p’ option.

  There are a couple of other things which I thinks its handy to know about patch, first is that not all patches will go on ‘cleanly’, sometimes you will get messages like ‘Hunk suceeded at offset 32’, this means that that part of the patch applied, but not in the exact same place as the original author intended. This happens all the time with the madwifi driver from cvs.

  Second is the -R swich for ‘patch’, this:

  CODE:

  $ cat /path/to/patch/patch.diff | patch -p1 -Rwould remove the patch from your current directory tree.
  And finally

  One last thing to remember: I am no expert, and some of this may be a bit wrong, missing something or whatever. Drop me a line if it is.