sed是一个面向行的流处理工具，主要用于对文件的增加、删除、替换等操作。
sed命令的语法：
sed [options] commands [file-to-edit]下面以annoying.txt文件作为示例数据源， 文件内容为：
root@a01:~/junk# echo "this is the song that never ends > yes, it goes on and on, my friend > some people started singing it > not knowing what it was > and they'll continue singing it forever > just because..." > annoying.txt 1. 命令及参数含义 1.1 读取文件内容如果 commands 为空，表示对每一行没有做任何处理，相当于读取文件的内容（因为sed默认会将读到的内容打印出来），如：
root@a01:~/junk# sed '' annoying.txt this is the song that never ends yes, it goes on and on, my friend some people started singing it not knowing what it was and they'll continue singing it forever just because...这与执行： # cat annoying.txt | sed '' 的输出是一样的。
1.2 打印命令pp命令将读到的内容直接打印出来， 如：
root@a01:~/junk# sed 'p' annoying.txt this is the song that never ends this is the song that never ends yes, it goes on and on, my friend yes, it goes on and on, my friend some people started singing it some people started singing it not knowing what it was not knowing what it was and they'll continue singing it forever and they'll continue singing it forever just because... just because...上面每一行都会打印两遍，是因为sed默认会将读到的内容输出，使用 -n 选项可以禁用默认的输出，如：
root@a01:~/junk# sed -n 'p' annoying.txt this is the song that never ends yes, it goes on and on, my friend some people started singing it not knowing what it was and they'll continue singing it forever just because...范围限制：可以在p命令前增加范围限制，数字表示具体的行数，+数字表示增量，$表示最后一行，~表示间隔的行数，如：
打印第1行：
root@a01:~/junk# sed -n '1p' annoying.txt this is the song that never ends打印第1行到第2行：
root@a01:~/junk# sed -n '1,2p' annoying.txt this is the song that never ends yes, it goes on and on, my friend打印第3行到最后一行：
root@a01:~/junk# sed -n '3,$p' annoying.txt some people started singing it not knowing what it was and they'll continue singing it forever just because...打印第1行到后面的2行，即前3行:
root@a01:~/junk# sed -n '1,+2p' annoying.txt this is the song that never ends yes, it goes on and on, my friend some people started singing it每隔2行打印，即打印奇数行：
root@a01:~/junk# sed -n '1~2p' annoying.txt this is the song that never ends some people started singing it and they'll continue singing it forever仅打印pattern匹配到的行：
root@a01:~/junk# sed -n '/this/p' annoying.txt this is the song that never ends 1.3 删除命令d删除命令d与打印命令p的用法基本类似，只需要将p换成d即可，如：
root@a01:~/junk# sed '1~2d' annoying.txt yes, it goes on and on, my friend not knowing what it was just because... root@a01:~/junk# sed '1,3d' annoying.txt not knowing what it was and they'll continue singing it forever just because...使用删除命令，没有被删的行会被打印出来，但是原文件是不被影响的。可以使用 -i 选项，表示在原文件上直接修改，
但是这样是比较危险的，最好先备份，而 -i 选项支持备份， -i 后面的参数值表示备份文件的后缀，如：
root@a01:~/junk# sed -i '1d' annoying.txt root@a01:~/junk# sed -i.bak '1d' annoying.txt root@a01:~/junk# ls annoying.txt annoying.txt.bak root@a01:~/junk# cat annoying.txt some people started singing it not knowing what it was and they'll continue singing it forever just because... root@a01:~/junk# cat annoying.txt.bak this is the song that never ends yes, it goes on and on, my friend some people started singing it not knowing what it was and they'll continue singing it forever just because... 1.4 替换命令s 's/old_word/new_word/'s是替换命令，/是默认的分隔符，也可以使用其它字符作为分隔符（紧跟s之后），常见的有：|, :, _等，注意末尾的分隔符不能省略。
old_word为正则表达式，用于匹配，new_word是要替换的字符串。如：
root@a01:~/junk# echo http://www.thegeekstuff.com/2009/09/unix-sed | sed 's_2009/09_2016/07_' http://www.thegeekstuff.com/2016/07/unix-seds命令默认仅替换每一行出现的第1个匹配，如：
root@a01:~/junk# sed 's/on/forward/' annoying.txt this is the sforwardg that never ends yes, it goes forward and on, my friend some people started singing it not knowing what it was and they'll cforwardtinue singing it forever just because...也可以仅替换每行的第n个匹配，如：
root@a01:~/junk# sed 's/on/forward/2' annoying.txt this is the song that never ends yes, it goes on and forward, my friend some people started singing it not knowing what it was and they'll continue singing it forever just because...全局替换使用g参数：
root@a01:~/junk# sed 's/on/forward/g' annoying.txt this is the sforwardg that never ends yes, it goes forward and forward, my friend some people started singing it not knowing what it was and they'll cforwardtinue singing it forever just because...如果仅替换独立的单词，不替换单词的部分，使用\b限制边界，如：
root@a01:~/junk# sed 's/\bon\b/forward/g' annoying.txt this is the song that never ends yes, it goes forward and forward, my friend some people started singing it not knowing what it was and they'll continue singing it forever just because...限制操作的行数，如仅全局替换前3行（&表示引用匹配到的部分）：
root@a01:~/junk# sed '1,2s/^.*/ &/' annoying.txt this is the song that never ends yes, it goes on and on, my friend some people started singing it not knowing what it was and they'll continue singing it forever just because...可以使用-n选项和p参数，打印仅发生替换的内容，如：
root@a01:~/junk# sed -n 's/on/forward/gp' annoying.txt this is the sforwardg that never ends yes, it goes forward and forward, my friend and they'll cforwardtinue singing it forever可见，在s命令的最后，可以通过参数影响替换的行为，如i表示忽略大小写：
root@a01:~/junk# sed -n 's/on/forward/gpi' annoying.txt this is the sforwardg that never ends yes, it goes forward and forward, my friend and they'll cforwardtinue singing it forever引用被匹配的部分：如果只有一个分组，则使用&比较方便，表示引用被匹配的部分，如：
root@a01:~/junk# sed 's/.*/| &/' annoying.txt | this is the song that never ends | yes, it goes on and on, my friend | some people started singing it | not knowing what it was | and they'll continue singing it forever | just because...如果有多个分组，首先在 old_word 里通过括号()分组，然后在 new_word 里通过数字序号去引用（分组的括号以及引用的数字都需要通过\转义）,
数字和前面的分组一一对应，最多可以使用9个数字。比如我们要反转每一行的前两个单词：
root@a01:~/junk# sed 's/\([0-9a-zA-Z][0-9a-zA-Z]*\) \([0-9a-zA-Z][0-9a-zA-Z]*\)/\2 \1/' annoying.txt is this the song that never ends yes, goes it on and on, my friend people some started singing it knowing not what it was they and'll continue singing it forever because just...\1可以用于用在new_word，也可以用在old_word中，如打印具有连续重复词的行：
root@a01:~/junk# sed -n '/\([a-z][a-z]*\) \1/p' annoying.txt this is the song that never ends 1.5 行之前插入命令i在文件中插入内容也是sed常见用法之一。i命令表示在匹配的行前插入内容，插入的内容作为一行显示，如：
root@a01:~/junk# sed '/singing/i before every line' annoying.txt this is the song that never ends yes, it goes on and on, my friend before every line some people started singing it not knowing what it was before every line and they'll continue singing it forever just because... 1.6 行之后插入命令a表示在匹配的行之后插入内容：
root@a01:~/junk# sed '/it/a after it' annoying.txt this is the song that never ends yes, it goes on and on, my friend after it some people started singing it after it not knowing what it was after it and they'll continue singing it forever after it just because... 1.7 行修改（替换）命令c root@a01:~/junk# sed '/it/c change it' annoying.txt this is the song that never ends change it change it change it change it just because... 1.8 执行多条处理命令：-e选项可以通过管道|，如：
root@a01:~/junk# sed 's/and/\&/' annoying.txt | sed 's/people/horses/' this is the song that never ends yes, it goes on & on, my friend some horses started singing it not knowing what it was & they'll continue singing it forever just because...但是因为需要多次调用sed命令，因此效率不好。推荐使用sed的 -e 选项来执行多条命令（只有一条命令时，-e选项不是必须的），如：
root@a01:~/junk# sed -e 's/and/\&/' -e 's/people/horses/' annoying.txt this is the song that never ends yes, it goes on & on, my friend some horses started singing it not knowing what it was & they'll continue singing it forever just because...还有一种方式，通过分号(;)将命令分割，如：
root@a01:~/junk# sed 's/and/\&/;s/people/horses/' annoying.txt this is the song that never ends yes, it goes on & on, my friend some horses started singing it not knowing what it was & they'll continue singing it forever just because... 1.9 sed脚本文件：-f选项可以将sed命令放到文件里，然后执行这个脚本文件，语法为：
$ sed -f script-file file-to-edit比如：
root@a01:~/junk# echo 's/and/\&/ > s/people/horses/' >> sed-demo root@a01:~/junk# sed -f sed-demo annoying.txt this is the song that never ends yes, it goes on & on, my friend some horses started singing it not knowing what it was & they'll continue singing it forever just because... 1.10 pattern命令前面都可以通过pattern去匹配，pattern为正则表达式。
比如仅处理包含singing这个词的行：
root@a01:~/junk# sed '/singing/s/it/& loudly/' annoying.txt this is the song that never ends yes, it goes on and on, my friend some people started singing it loudly not knowing what it was and they'll continue singing it loudly forever just because...pattern默认的分隔符也是/，如果第一个字符为\，则使用后面的字符作为分隔符，一般用于匹配本身带有/的值，如：
root@a01:~/junk# echo http://www.grymoire.com/Unix/sed.html | sed '\_/Unix/sed_s_/sed_/awk_' http://www.grymoire.com/Unix/awk.htmlpattern除了直接匹配，还支持范围匹配，语法为：
sed '/start/,/stop/ s/#.*//'start表示匹配开始，stop表示匹配结束，可以看作开关；如果是正则表达式，需要使用//，如果只是数字或者^$，则不需要//。
删除从some开头到not开头的中间所有行：
root@a01:~/junk# sed '/^some/,/^not/d' annoying.txt this is the song that never ends yes, it goes on and on, my friend and they'll continue singing it forever just because...删除第1行到包含yes的那一行：
root@a01:~/junk# sed '1,/yes/d' annoying.txt some people started singing it not knowing what it was and they'll continue singing it forever just because...删除包含yes那行到最后一行（命令d前面允许有空格的）：
root@a01:~/junk# sed '/yes/,$ d' annoying.txt this is the song that never ends命令前面使用!表示对命令取反，比如对上一条命令取反：
root@a01:~/junk# sed '/^some/,/^not/!d' annoying.txt some people started singing it not knowing what it was 2. 应用示例 2.1 保留每一行的第一个单词 root@a01:~/junk# sed 's/\([a-zA-Z]*\).*/\1/' < annoying.txt > first_word.txt root@a01:~/junk# cat first_word.txt this yes some not and just 2.2 Here is 输入root@a01:~/junk# cat sed-here-is.sh #!/bin/sh echo -n "what is the value?\n" read value sed "s/XYZ/$value/" <<EOF The value is XYZ EOF root@a01:~/junk# sh sed-here-is.sh what is the value? test The value is test 参考 Sed - An Introduction and Tutorial by Bruce Barnett The Basics of Using the Sed Stream Editor to Manipulate Text in linux Intermediate Sed: Manipulating Streams of Text in a Linux Environment