Linux下的diff和patch命令

1.Patch命令的基本语法

The patch command takes a patch file patchfile containing a difference listing produced by the diff program and applies those differences to one or more original files, producing patched versions. Normally the patched versions are put in place of the originals.（patch是通过由diff命令产生的记录文件之间不同之处的补丁文件；默认情况下是在原文件的基础之上进行修改的）

The basic syntax is as follows:

$ patch < patch.file
$ patch source.code.file < patch.file
$ patch -p LEVEL < {/path/to/patch/file}

To apply a patch, one could run the following command in a shell:

$ patch < /path/to/file

In this example, patch foo.c with patch.diff file:

$ patch foo.c < patch.diff

Patches can be undone, or reversed, with the ‘-R’ option（使用”-R”选项撤销patch操作）:

$ patch -R < /path/to/file

2.创建patch补丁文件

How do I create a patch? To create a patch, one could run the following diff command:

$ diff -u oldfile-name-here newfile-name-here > patch.diff

3.如何给一个源码树打补丁？

A note about working on an entire source tree

First, make a copy of the source tree:

## Original source code is in lighttpd-1.4.35/ directory ##
$ cp -R lighttpd-1.4.35/ lighttpd-1.4.35-new/

Cd to lighttpd-1.4.35-new directory and make changes as per your requirements:

$ cd lighttpd-1.4.35-new/
$ vi geoip-mod.c
$ vi Makefile

Finally, create a patch with the following command:

$ cd ..
$ diff -rupN lighttpd-1.4.35/ lighttpd-1.4.35-new/ > my.patch

You can use my.patch file to patch lighttpd-1.4.35 source code on a different computer/server using patch command as discussed above:

$ patch -p1 < my.patch

 

参考链接：

• http://www.cyberciti.biz/faq/appy-patch-file-using-patch-command/
• Linux命令学习手册-patch命令
• http://jungels.net/articles/diff-patch-ten-minutes.html
• http://ftp.gnu.org/gnu/bash/
• http://www.stevejenkins.com/blog/2014/09/how-to-manually-update-bash-to-patch-shellshock-bug-on-older-fedora-based-systems/