uniq命令：
uniq [OPTION]... [FILE]...
-c: 顯示每行重復(fù)出現(xiàn)的次數(shù)；

[root@ansible ~]# cat test.txt 
this is test
this is test
this is your list
this is this
[root@ansible ~]# uniq -c test.txt 
      2 this is test
      1 this is your list
      1 this is this

-d: 僅顯示重復(fù)過的行；

[root@ansible ~]# cat test.txt 
this is test
this is test
this is your list
this is this
[root@ansible ~]# uniq -d test.txt 
this is test

-u: 僅顯示不曾重復(fù)的行；

[root@ansible ~]# cat test.txt 
this is test
this is test
this is your list
this is this
[root@ansible ~]# uniq -u test.txt 
this is your list
this is this