Introduction to the Linux centos7 sed tool

First, the SED

The Grep tool feature can only be found and cannot replace the found content.

SED itself is a pipeline command, mainly in the Behavior unit processing, can be the data row to find, delete, replace characters or strings, swap string location , directly modify the contents of the file and other specific work, for the document's lines, such as. txt.

[Email protected] ~]# mkdir SED
[[Email protected] ~]# CD SED
[email protected] sed]# CP. /GREP/PASSWD 0.txt
[Email protected] sed]#
[Email protected] sed]# pwd
/root/sed
[[email protected] sed]# ls
0.txt
[Email protected] sed]#

find:sed-n '/keywords/' p filename

[[email protected] sed]# sed-n ' 2 ' P 0.txt show second line

[[Email protected] sed]# sed ' 15,$ ' p 0.txt display 15 lines to the last line

[[email protected] sed]# sed-n ' 1,$ ' P 0.txt Show all

[[email protected] sed] #sed-n '/^1/' P 0.txt

[[email protected] sed] #sed-n '/in$/' P 0.txt

[[email protected] sed] #sed-n '/R. o/' P 0.txt

[[email protected] sed] #sed-n '/oo*/' P 0.txt

[[email protected] sed] #sed-n '/oo*/' Ip 0.txt Add uppercase I, case-insensitive

Delete:sed-n ' keyword ' p file name, simply list the rows not deleted in the screen, in fact the original file is not deleted.

[[email protected] sed] #sed-n ' 5 ' p 0.txt

[[email protected] sed] #sed-n ' 1,5 ' p 0.txt

[[email protected] sed] #sed-n ' 1,$ ' P 0.txt

[[email protected] sed] #sed-n '/root/' P 0.txt

[[email protected] sed] #sed-n '/^1/' P 0.txt

[[email protected] sed] #sed-n '/in$/' P 0.txt

[[email protected] sed] #sed-n '/R. o/' P 0.txt

[[email protected] sed] #sed-n '/oo*/' P 0.txt

Replace: s denotes substitution action, G denotes the bank's global substitution, except with/As a delimiter, can also use special characters #, @

[[Email protected] sed]# sed ' 1,2s/ot/to/g ' 0.txt 12th line, OT replaced with to

[Email protected] sed]# sed-r ' 1,2s/ot+/to/g ' 0.txt

[[Email protected] sed]# sed ' s#ot#to#g ' 0.txt

[Email protected] sed]# sed ' [email protected]@[email protected] ' 0.txt

[[Email protected] sed]# sed ' s/[0-9]//g ' 0.txt

[[Email protected] sed]# sed ' s/[a-za-z]//g ' 0.txt

Swap two character positions

[[Email protected] sed]# sed ' s/\ (root\) \ (. *\) \ (bash\)/\3\2\1/' 0.txt

[[email protected] sed]# Sed-r ' s/(Root) (. *) (bash)/\3\2\1/' 0.txt join-R expression clearer

Bash:x:0:0:root:/root:/bin/root

[Email protected] sed]# sed-r ' s/(Uaer) (. *) (bash)/\3\2\1/' 0.txt

Bash1:x:1001:1004::/home/uaer1:/bin/uaer

[[Email protected] sed]# sed ' s/^.*$/123&/' 0.txt front plus 123

123root:x:0:0:root:/root:/bin/bash
123bin:x:1:1:bin:/bin:/sbin/nologin

Modify file Contents directly

[Email protected] sed]# sed-i ' s/root/toor/g ' 0.txt
[email protected] sed]# cat 0.txt
Toor:x:0:0:toor:/toor:/bin/bash

Example

[[email protected] sed]# sed '/root/' P 0.txt will show all rows
Root:x:0:0:root:/root:/bin/bash
Root:x:0:0:root:/root:/bin/bash
Bin:x:1:1:bin:/bin:/sbin/nologin
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
[[email protected] sed]# sed-n '/root/' P 0.txt just show the keyword target line
Root:x:0:0:root:/root:/bin/bash
Operator:x:11:0:operator:/root:/sbin/nologin

[[email protected] sed]# sed-nr '/root|bus/' P 0.txt join R

Root:x:0:0:root:/root:/bin/bash
Operator:x:11:0:operator:/root:/sbin/nologin

[Email protected] sed]# sed-nr '/o+t/' P 0.txt
Root:x:0:0:root:/root:/bin/bash
Operator:x:11:0:operator:/root:/sbin/nologin

Dbus:x:81:81:system message Bus:/:/sbin/nologin

[Email protected] sed]# sed-nr '/o{2}/' P 0.txt
Root:x:0:0:root:/root:/bin/bash
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

Introduction to the Linux centos7 sed tool