diff & patch

1. diff
%和空格有关的选项

• -E：忽略因把制表符扩展为空格而造成的差异
• -b：忽略因空白符的数目而造成的差异
• -w：忽略所有空白符
• -B：忽略空行（指连空白符都没有的行）

%忽略大小写： -i

%忽略所有差异都匹配正则表达式的行： -I regexp

%只列出哪些文件互不相同： -q

%输入格式

• without context

change-command
< from-file-line
< from-file-line...
---
> to-file-line
> to-file-line...
change-command可以是：(lar，Add the lines in range r of the second file after line l of the first file.或fct，Replace the lines in range f of the first file with lines in range t of the second file.或rdl，Delete the lines in range r from the first file; line l is where they would have appeared in the second file had they not been deleted)

• with context

选项：-C num 或 -c
输出格式：
*** from-file from-file-modification-time
--- to-file to-file-modification time
***************
*** from-file-line-range ****
  from-file-line
  from-file-line...
--- to-file-line-range ----
  to-file-line
  to-file-line...
上下文以两个空格开始，不同的同以+,-,或!及后跟一个空格开始
!
    A line that is part of a group of one or more lines that changed between the two files. There is a corresponding group of lines marked with ! in the part of this hunk for the other file.
+
    An "inserted" line in the second file that corresponds to nothing in the first file.
-
    A "deleted" line in the first file that corresponds to nothing in the second file.

• unified format

选项：-U num 或 -u
输出格式：
--- from-file from-file-modification-time
+++ to-file to-file-modification-time
@@ from-file-range to-file-range @@
 line-from-either-file
 line-from-either-file...
The lines common to both files begin with a space character. The lines that actually differ between the two files have one of the following indicator characters in the left print column:

+
    A line was added here to the first file.
-
    A line was removed here from the first file.
注意前面两种格式的输出都涉及到两个文件，而unified格式只涉及第一个文件，所以比较简洁。