sed 想刪除文件中的指定行，是可以用行號指定也可以用RE來匹配的。
刪除指定的行【可以指定行號刪除、匹配字符串來刪除】
[root@Jason64-17 ~]# cat -n seq.txt
1 ok i will help you
2 understand sed usage
3 how to use it
4 and we should use it in view
5 now let us
6 go
7 hello my name is
[root@Jason64-17 ~]# cat -n seq.txt | sed 3d
1 ok i will help you
2 understand sed usage
4 and we should use it in view
5 now let us
6 go
7 hello my name is
[root@Jason64-17 ~]# cat -n seq.txt | sed /should/d
1 ok i will help you
2 understand sed usage
3 how to use it
5 now let us
6 go
7 hello my name is
[root@Jason64-17 ~]# cat -n seq.txt | sed /ow/d
1 ok i will help you
2 understand sed usage
4 and we should use it in view
6 go
7 hello my name is
[root@Jason64-17 ~]# cat -n seq.txt | sed -r /how\|should/d
1 ok i will help you
2 understand sed usage
5 now let us
6 go
7 hello my name is刪除最後幾行
[root@Jason64-17 ~]# seq 5 > seq01.txt [root@Jason64-17 ~]# cat seq01.txt 1 2 3 4 5 [root@Jason64-17 ~]# for((i=1;i<4;i++)); do sed -i '$d' seq01.txt ; done #C式for循環 [root@Jason64-17 ~]# cat seq01.txt 1 2 [root@Jason64-17 ~]# seq 5 > seq01.txt [root@Jason64-17 ~]# cat seq01.txt 1 2 3 4 5 [root@Jason64-17 ~]# i=1; while [ $i -le 3 ]; do sed -i '$d' seq01.txt; ((i++)); done #while循環 [root@Jason64-17 ~]# cat seq01.txt 1 2 [root@Jason64-17 ~]# seq 5 > seq01.txt [root@Jason64-17 ~]# cat seq01.txt 1 2 3 4 5 [root@Jason64-17 ~]# for i in `seq 3`; do sed -i '$d' seq01.txt ; done #bash for循環 [root@Jason64-17 ~]# cat seq01.txt 1 2 [root@Jason64-17 ~]# seq 5 > seq01.txt [root@Jason64-17 ~]# cat seq01.txt 1 2 3 4 5 #until 循環 [root@Jason64-17 ~]# seq 5 > seq01.txt [root@Jason64-17 ~]# cat seq01.txt 1 2 3 4 5 [root@Jason64-17 ~]# i=3; until [ $i -le 0 ]; do sed -i '$d' seq01.txt ; ((i--)); done [root@Jason64-17 ~]# cat seq01.txt 1 2 [root@Jason64-17 ~]#
上述例子都是刪除了最後3行的要求。