sed的全称是 stream editor，是支持正则表达式的流编辑器。其作用便是将文本文件或来自于管道符传入的输入流进行文本处理，如替换、增加内容、删除内容等等。
一、基本参数
下面对各个参数举例说明，以此文件为例：
shiyanlou:~/ $ nl a.txt
1 Nice to meet you p2p
2 Where you've been?
3 I can show you incredible things
4 Magic, madness, heaven, (sins)
5 Saw you there and I thought oh my_god
6 Look at that face, you lookokok like my next mistake404
7 Look at that face, you loook like my next mistake404
8 Love's a game, wanna play
9 New money, suit and tie
10 I can read you like a magazine
shiyanlou:~/ $
1.1 d 删除指定行：
shiyanlou:~/ $ nl a.txt | sed '2,5d' # 删除 2~5 行
1 Nice to meet you p2p
6 Look at that face, you lookokok like my next mistake404
7 Look at that face, you loook like my next mistake404
8 Love's a game, wanna play
9 New money, suit and tie
10 I can read you like a magazine
shiyanlou:~/ $
shiyanlou:~/ $ nl a.txt | sed '7,$d' # 删除 7 至最后一行
1 Nice to meet you p2p
2 Where you've been?
3 I can show you incredible things
4 Magic, madness, heaven, (sins)
5 Saw you there and I thought oh my_god
6 Look at that face, you lookokok like my next mistake404
shiyanlou:~/ $
shiyanlou:~/ $ nl a.txt | sed '$d' # 删除最后一行
1 Nice to meet you p2p
2 Where you've been?
3 I can show you incredible things
4 Magic, madness, heaven, (sins)
5 Saw you there and I thought oh my_god
6 Look at that face, you lookokok like my next mistake404
7 Look at that face, you loook like my next mistake404
8 Love's a game, wanna play
9 New money, suit and tie
shiyanlou:~/ $
1.2 -i 修改原文件：
shiyanlou:~/ $ sed -i '1d' a.txt # 删除第一行
shiyanlou:~/ $ nl a.txt # 打印文件，第一行没了
1 Where you've been?
2 I can show you incredible things
3 Magic, madness, heaven, (sins)
4 Saw you there and I thought oh my_god
5 Look at that face, you lookokok like my next mistake404
6 Look at that face, you loook like my next mistake404
7 Love's a game, wanna play
8 New money, suit and tie
9 I can read you like a magazine
shiyanlou:~/ $
1.3 a 在某行后面添加一行字符串：
shiyanlou:~/ $ nl a.txt | sed '2a 今天天气不错。' # 在第 2 行后面添加一行字符串
1 Where you've been?
2 I can show you incredible things
今天天气不错。
3 Magic, madness, heaven, (sins)
4 Saw you there and I thought oh my_god
5 Look at that face, you lookokok like my next mistake404
6 Look at that face, you loook like my next mistake404
7 Love's a game, wanna play
8 New money, suit and tie
9 I can read you like a magazine
shiyanlou:~/ $
1.4 i 在某行前面添加一行字符串：
shiyanlou:~/ $ nl a.txt | sed '2i 哈哈' # 在第 2 行前面添加一行
1 Where you've been?
哈哈
2 I can show you incredible things
3 Magic, madness, heaven, (sins)
4 Saw you there and I thought oh my_god
5 Look at that face, you lookokok like my next mistake404
6 Look at that face, you loook like my next mistake404
7 Love's a game, wanna play
8 New money, suit and tie
9 I can read you like a magazine
shiyanlou:~/ $
1.5 c 将指定行替换为字符串：
shiyanlou:~/ $ nl a.txt | sed '6,$c hello world' # 将 6 至尾行替换为字符串
1 Where you've been?
2 I can show you incredible things
3 Magic, madness, heaven, (sins)
4 Saw you there and I thought oh my_god
5 Look at that face, you lookokok like my next mistake404
hello world
shiyanlou:~/ $
1.6 -n 只打印受影响的行；p 复制某行并打印，通常配合 -n 一起用：
shiyanlou:~/ $ nl a.txt | sed '5,7p'
1 Where you've been?
2 I can show you incredible things
3 Magic, madness, heaven, (sins)
4 Saw you there and I thought oh my_god
5 Look at that face, you lookokok like my next mistake404
5 Look at that face, you lookokok like my next mistake404
6 Look at that face, you loook like my next mistake404
6 Look at that face, you loook like my next mistake404
7 Love's a game, wanna play
7 Love's a game, wanna play
8 New money, suit and tie
9 I can read you like a magazine
shiyanlou:~/ $ nl a.txt | sed -n '5,7p'
5 Look at that face, you lookokok like my next mistake404
6 Look at that face, you loook like my next mistake404
7 Love's a game, wanna play
shiyanlou:~/ $
1.7 G 使文件中每一行下面添加一个空行：
shiyanlou:~$ nl a.txt | sed 'G'
1 Where you've been?
2 I can show you incredible things
3 Magic, madness, heaven, (sins)
4 Saw you there and I thought oh my_god
5 Look at that face, you lookokok like my next mistake404
6 Look at that face, you loook like my next mistake404
7 Love's a game, wanna play
8 New money, suit and tie
9 I can read you like a magazine
1.8 ! 反操作：
shiyanlou:~$ nl a.txt | sed '4,$!G' # 4 行及以下不执行
1 Where you've been?
2 I can show you incredible things
3 Magic, madness, heaven, (sins)
4 Saw you there and I thought oh my_god
5 Look at that face, you lookokok like my next mistake404
6 Look at that face, you loook like my next mistake404
7 Love's a game, wanna play
8 New money, suit and tie
9 I can read you like a magazine
二、高级用法
以此文件为例：
shiyanlou:~/ $ nl words.txt
1 syl
2 I hate shiyanlou
3 syl
2.1 s 行内替换，多重命令使用 ; 隔开，-e 和“分行”亦可实现多重命令：
shiyanlou:~/ $ sed 's/syl/shiyanlou/; s/hate/love/' words.txt
shiyanlou
I love shiyanlou
shiyanlou
shiyanlou:~/ $
shiyanlou:~/ $ sed -e 's/syl/haha/' -e 's/hate/love/' words.txt
haha
I love shiyanlou
haha
shiyanlou:~/ $
shiyanlou:~/ $ sed ' # 分行
quote> s/syl/haha/
quote> s/hate/love/' words.txt
haha
I love shiyanlou
haha
shiyanlou:~/ $
2.2 g 无它，只替换每行第一个字段；有它，替换全部：
shiyanlou:~$ nl words.txt | sed 's/a/A/'
1 sys
2 I hAte shiyanlou.
3 sys
shiyanlou:~$ nl words.txt | sed 's/a/A/g'
1 sys
2 I hAte shiyAnlou.
3 sys
shiyanlou:~$
2.3 -f 选项执行 sed 脚本文件：
shiyanlou:~/ $ echo "s/syl/haha/\ns/hate/love/" > sfile
shiyanlou:~/ $ nl sfile
1 s/syl/haha/
2 s/hate/love/
shiyanlou:~/ $ sed -f sfile words.txt
haha
I love shiyanlou
haha
shiyanlou:~/ $
2.4 将 shebang 写入脚本文件，赋予其可执行权限，即可直接执行：
shiyanlou:~/ $ which sed # 查找 sed 命令的可执行文件
/bin/sed
# 将 shebang 插入到文件的第一行
shiyanlou:~/ $ sed -i '1i #!/bin/sed -f' sfile
shiyanlou:~/ $ nl sfile
1 #!/bin/sed -f
2 s/syl/haha/
3 s/hate/love/
shiyanlou:~/ $ chmod +x sfile
shiyanlou:~/ $ ./sfile words.txt
haha
I love shiyanlou
haha
2.5 寻址
上文中使用
s选项对文件进行修改，默认是全文修改。实际上我们在使用sed命令处理流数据时，经常需要对特定的行进行修改，这就用到了“寻址”之术。
使用下面的文件进行举例：
shiyanlou:~/ $ cat -n xunzhi
1 a b
2 b
3 c
4
5 d b
6
7 e
8
9 f
2.5.1 将字符 a 所在的行的字符 b 替换为 haha：
shiyanlou:~/ $ nl xunzhi | sed '/a/s/b/haha/'
1 a haha
2 b
3 c
4 d b
5 e
6 f
shiyanlou:~/ $
2.5.2 /^&/ 表示空行：
shiyanlou:~/ $ cat xunzhi # nl 命令虽然不给空行编号，但打印结果空行不是没有字符的
a b
b
c
d b
e
f
shiyanlou:~/ $ cat xunzhi | sed '/^$/d' # 删掉全部空行
a b
b
c
d b
e
f
shiyanlou:~/ $
shiyanlou:~/ $ cat xunzhi | sed '2,/^$/d' # 删掉第 2 行到第 1 个空行
a b
d b
e
f
shiyanlou:~/ $
2.5.3 { } 大括号可实现分组
先将 xunzhi 文件中包含 b 字符又包含 hello 字符串的行（即第 1、3 行）中的 world 替换为 shiyanlou，再将包含 b 和 d 字符的行（即第 5 行）中的 world 替换为 louplus：
shiyanlou:~/ $ cat -n xunzhi # 修改后的 xunzhi 文件
1 a b hello world
2 b world
3 c b d hello world
4
5 d b world good
6
7 e hello world
shiyanlou:~/ $ sed '/b/{
quote> /hello/s/world/shiyanlou/
quote> /d /s/world/louplus/ # 此处的 d 为特殊字符，且不能被转义
quote> }' xunzhi | cat -n # 所以在其后面加个空格，成为 'd '
1 a b hello shiyanlou # 否则只匹配前面的 'b' 字符，那么第 2 行也将被修改
2 b world
3 c b d hello shiyanlou
4
5 d b louplus good
6
7 e hello world
shiyanlou:~/ $
2.6 -r 参数使用标准正则表达式，上面 2.5.3 的例子可以这样写：
shiyanlou:~/ $ sed -r '/b/{
quote> /hello/s/world/shiyanlou/
quote> /\d/s/hello/louplus/ # d 为特殊字符，须转义
quote> }' xunzhi | cat -n
1 a b hello shiyanlou
2 b world
3 c b d louplus shiyanlou
4
5 d b world good
6
7 e hello world
shiyanlou:~/ $
