文件比较是非常需要的功能，比如判断两个程序的源码文件的不同版本的差异。BeyondCompare尽管功能强大，但要注册；Meld也是不错的工具，也可以跨平台。有没有轻量级的工具呢？在Linux下有diff和sdiff，Windows下有WinDiff，基本的文件差异比较能达到，值得考虑。
下面这个是对diff和sdiff的介绍，原文来自：https://www.cyberciti.biz/faq/how-do-i-compare-two-files-under-linux-or-unix/
How do I Compare two files under Linux or UNIX?
You need to use diff command to display line-by-line difference between two files. The general syntax of diff command as follows:
diff FILE1 FILE2
Where,
FILE1 FILE2: Diff command will examine both file1 and file2 and tells you what changes need to be made for file1 and file2 to match. Please note that diff command point to which lines need be:
- Added (a)
- Deleted (d)
- Changed (c)
- Further lines in file1 identified with a less than () symbol and lines in file2 with a grater than (>) symbol.
Examples
diff file1.txt file2.txt
Output:
8c8,9 URL: www.nixcraft.in > Email: [email protected]
The contents of both files:
$ cat file1.txt
Output:
Welcome to nixCraft! If undeliverd return to nixCraft #404, DC bay area, 2nd phase, Pune. Ph: 555-11112223 URL: www.nixcraft.com
$ cat file2.txt
Output:
Welcome to nixCraft! If undeliverd return to nixCraft #404, DC bay area, 2nd phase, Pune. Ph: 555-11112223 URL: www.nixcraft.in Email: [email protected]
Side-by-side merge of file differences
You can get a clear-cut visual difference between two text files using the command sdiff:
$ sdiff file1.txt file2.txt
Output:
Welcome to nixCraft! Welcome to nixCraft!
If undeliverd return to nixCraft If undeliverd return to nixCraft
#404, DC bay area, 2nd phase, #404, DC bay area, 2nd phase,
Pune. Pune.
Ph: 555-11112223 Ph: 555-11112223
URL: www.nixcraft.com | URL: www.nixcraft.in
> Email: [email protected]