sed
准备工作：
root@am-01:~# mkdir sed root@am-01:~# cp grep/passwd sed/test.txt root@am-01:~# ls sed/ test.txt root@am-01:~# cd sed/ root@am-01:~/sed# pwd /root/sed
匹配带有root的行(-n)
root@am-01:~/sed# sed -n ‘/root/‘p test.txt root:x:0:0:rooot:/root:/bin/bash operator:x:11:0:operator:/root:/sbin/nologin
例子o+t，匹配+号左边的字符1次或多次的行打印出来(-r)
root@am-01:~/sed# sed -nr ‘/o+t/‘p test.txt root:x:0:0:rooot:/root:/bin/bash operator:x:11:0:operator:/root:/sbin/nologin
例子o{2}，匹配带有连续两个o的行
root@am-01:~/sed# sed -nr ‘/o{2}/‘p test.txt root:x:0:0:rooot:/root:/bin/bash sadas:r.oooo lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin mail:x:8:12:mail:/var/spool/mail:/sbin/nologin operator:x:11:0:operator:/root:/sbin/nologin postfix:x:89:89::/var/spool/postfix:/sbin/nologin
匹配包含root或者bus的行
root@am-01:~/sed# sed -nr ‘/root|bus/‘p test.txt root:x:0:0:rooot:/root:/bin/bash operator:x:11:0:operator:/root:/sbin/nologin dbus:x:81:81:System message bus:/:/sbin/nologin
打印第二行和打印第二行到第五行
root@am-01:~/sed# sed -n ‘2‘p test.txt bin:x:1:1:bin:/bin:/sbin/NOLogin root@am-01:~/sed# sed -n ‘2,5‘p test.txt bin:x:1:1:bin:/bin:/sbin/NOLogin sadas:r.oooo dsgfgf:r1o: daemon:x:2:2:daemon:/sbin:/sbin/nologin
打印第二十行到最后一行，$表示末行
root@am-01:~/sed# sed -n ‘20,$‘p test.txt postfix:x:89:89::/var/spool/postfix:/sbin/nologin sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin aming:x:1000:1000::/home/aming:/bin/bash ntp:x:38:38::/etc/ntp:/sbin/nologin user1:x:1001:1001::/home/user1:/bin/bash user2:x:1002:1002::/home/user2:/bin/bash user3:x:1003:1005::/home/user3:/bin/bash user4:x:1004:1005::/home/aming111:/sbin/nologin user5:x:1005:1006::/home/user5:/bin/bash user6:x:1007:1007::/home/user6:/bin/bash
同一个表达式做多个操作，可以加-e参数
root@am-01:~/sed# sed -e ‘/root/‘p -e ‘1‘p -n test.txt root:x:0:0:rooot:/root:/bin/bash root:x:0:0:rooot:/root:/bin/bash operator:x:11:0:operator:/root:/sbin/nologin
匹配的时候不区分大小写
root@am-01:~/sed# vim test.txt #随便一行添加大写的BUS，便于做实验 dsgfgf:r1o:BUS root@am-01:~/sed# sed -n ‘/bus/‘Ip test.txt dsgfgf:r1o:BUS dbus:x:81:81:System message bus:/:/sbin/nologin
把文件除了1-25行之外的都匹配出来，d是删除的意思(不会对文件本身做操作)
root@am-01:~/sed# sed ‘1,25‘d test.txt user3:x:1003:1005::/home/user3:/bin/bash user4:x:1004:1005::/home/aming111:/sbin/nologin user5:x:1005:1006::/home/user5:/bin/bash user6:x:1007:1007::/home/user6:/bin/bash
选项-i会删除文件中指定的内容(会对文件本身做操作)
root@am-01:~/sed# sed -i ‘1,25‘d test.txt root@am-01:~/sed# wc -l test.txt 4 test.txt
指定删除含有某个关键字的一行(会对文件本身做操作)
root@am-01:~/sed# sed -i ‘/user3/‘d test.txt root@am-01:~/sed# cat test.txt user4:x:1004:1005::/home/aming111:/sbin/nologin user5:x:1005:1006::/home/user5:/bin/bash user6:x:1007:1007::/home/user6:/bin/bash
查找1-10行的root，替换为toor
root@am-01:~/sed# sed ‘1,10s/root/toor/g‘ test.txt | head toor:x:0:0:rooot:/toor:/bin/bash bin:x:1:1:bin:/bin:/sbin/NOLogin sadas:r.oooo dsgfgf:r1o: daemon:x:2:2:daemon:/sbin:/sbin/nologin adm:x:3:4:adm:/var/adm:/sbin/nologin lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin sync:x:5:0:sync:/sbin:/bin/sync shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown halt:x:7:0:halt:/sbin:/sbin/halt
查找1-10行，无论+号左边的字符ro出现过1次或多次，都把它替换为r(切记在sed中有+号需要用-r参数)
root@am-01:~/sed# sed -r ‘1,10s/ro+/r/g‘ test.txt | head rt:x:0:0:rt:/rt:/bin/bash bin:x:1:1:bin:/bin:/sbin/NOLogin sadas:r.oooo dsgfgf:r1o: daemon:x:2:2:daemon:/sbin:/sbin/nologin adm:x:3:4:adm:/var/adm:/sbin/nologin lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin sync:x:5:0:sync:/sbin:/bin/sync shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown halt:x:7:0:halt:/sbin:/sbin/halt
把1-10行的行首和行尾替换位置
这里每一个括号的内容跟后面的1/2/3相对应，其中(.*):指的是贪婪匹配到最后一个冒号的位置
root@am-01:~/sed# head test.txt| sed -r ‘s/([^:]+):(.*):([^:]+)/\3:\2:\1/g‘ /bin/bash:x:0:0:rooot:/root:root /sbin/NOLogin:x:1:1:bin:/bin:bin sadas:r.oooo dsgfgf:r1o: /sbin/nologin:x:2:2:daemon:/sbin:daemon /sbin/nologin:x:3:4:adm:/var/adm:adm /sbin/nologin:x:4:7:lp:/var/spool/lpd:lp /bin/sync:x:5:0:sync:/sbin:sync /sbin/shutdown:x:6:0:shutdown:/sbin:shutdown /sbin/halt:x:7:0:halt:/sbin:halt
如果有多个斜杠或特殊符号就需要脱义
root@am-01:~/sed# head test.txt| sed ‘s/\/sbin\/nologin/123/g‘ root:x:0:0:rooot:/root:/bin/bash bin:x:1:1:bin:/bin:/sbin/NOLogin sadas:r.oooo dsgfgf:r1o: daemon:x:2:2:daemon:/sbin:123 adm:x:3:4:adm:/var/adm:123 lp:x:4:7:lp:/var/spool/lpd:123 sync:x:5:0:sync:/sbin:/bin/sync shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown halt:x:7:0:halt:/sbin:/sbin/halt root@am-01:~/sed# head test.txt| sed ‘s@/sbin/nologin@123@g‘ root:x:0:0:rooot:/root:/bin/bash bin:x:1:1:bin:/bin:/sbin/NOLogin sadas:r.oooo dsgfgf:r1o: daemon:x:2:2:daemon:/sbin:123 adm:x:3:4:adm:/var/adm:123 lp:x:4:7:lp:/var/spool/lpd:123 sync:x:5:0:sync:/sbin:/bin/sync shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown halt:x:7:0:halt:/sbin:/sbin/halt
把英文字母都删除掉(不会对文件本身做操作)
root@am-01:~/sed# head test.txt | sed ‘s/[a-zA-Z]//g‘ ::0:0::/:// ::1:1::/:// :. :1: ::2:2::/:// ::3:4:://:// ::4:7::///:// ::5:0::/:// ::6:0::/:// ::7:0::/://
在所有行前面加上固定的字符(\1和&的意思一样，有特殊符号需要加-r)
root@am-01:~/sed# head test.txt | sed -r ‘s/(.*)/aaa:\1/g‘ aaa:root:x:0:0:rooot:/root:/bin/bash aaa:bin:x:1:1:bin:/bin:/sbin/NOLogin aaa:sadas:r.oooo aaa:dsgfgf:r1o: aaa:daemon:x:2:2:daemon:/sbin:/sbin/nologin aaa:adm:x:3:4:adm:/var/adm:/sbin/nologin aaa:lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin aaa:sync:x:5:0:sync:/sbin:/bin/sync aaa:shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown aaa:halt:x:7:0:halt:/sbin:/sbin/halt root@am-01:~/sed# head test.txt | sed -r ‘s/(.*)/aaa:&/g‘ aaa:root:x:0:0:rooot:/root:/bin/bash aaa:bin:x:1:1:bin:/bin:/sbin/NOLogin aaa:sadas:r.oooo aaa:dsgfgf:r1o: aaa:daemon:x:2:2:daemon:/sbin:/sbin/nologin aaa:adm:x:3:4:adm:/var/adm:/sbin/nologin aaa:lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin aaa:sync:x:5:0:sync:/sbin:/bin/sync aaa:shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown aaa:halt:x:7:0:halt:/sbin:/sbin/halt
