diff
===



## 

**diff** -diff

###  

```shell
diff()()
```

###  

```shell
--c-u
-atextdiff
-b--ignore-space-change
-B--ignore-blank-lines
-c
-C--context-c-
-dminimal
-Difdef
-eededscript
-f-forward-ededscript
-H--speed-large-files
-l--ignore-matching-lines
-i--ignore-case
-lpaginatepr
-nrcsRCS
-N--new-fileAOnly inA -NdiffA 
-pC
-P--unidirectional-new-file-N
-q--brief
-rrecursive
-s--report-identical-files
-S--starting-file
-t--expand-tabstab
-T--initial-tabtab
-u-U--unified=
-vversion
-w--ignore-all-space
-W--width-y
-x--exclude
-X--exclude-from=
-y--side-by-side
--help
--left-column-y
--suppress-common-lines-y
```

###  

*   1
*   2

###  

#### 

```shell
diff a.txt b.txt
```

####  (context) 

```shell
diff -c a.txt b.txt
```

```
*** a1.txt 2012-08-29 16:45:41.000000000 +0800
--- a2.txt 2012-08-29 16:45:51.000000000 +0800
***************
*** 1,7 ****
 a
 a
 a
!a
 a
 a
 a
--- 1,7 ----
 a
 a
 a
!b
 a
 a
 a
```

####  (unified) 

```shell
diff -u a.txt b.txt
```

```
--- a.txt 2012-08-29 16:45:41.000000000 +0800
+++ b.txt 2012-08-29 16:45:51.000000000 +0800
@@ -1,7 +1,7 @@
 a
 a
 a
-a
+b
 a
 a
 a
```

#### 

`/usr/li`"test.txt""test.txt"

```shell
diff /usr/li test.txt     #diff
```



```shell
n1 a n3,n4  
n1,n2 d n3  
n1,n2 c n3,n4 
```

"a""d""c""n1""n2"1"n3""n4"2

2