SED and awk tools of shell

Such as ： stay 2~50 That's ok Add... At the beginning of the line # Note No

：2,50 s/^/#/g

sed

Output all matching character lines

sed -n
"/ character /p" file name

Delete all matching character lines

sed -i
"/ character /d" file name

Replace all matching characters with target characters

sed -i
"s/ character / Target character /g" file name

Replace the matching character of the specified line with the target character

sed -e
'2s/xxxx/yyyy/4' yf.txt

notes ： there 2, It means the first one 2 That's ok .

?? there 3, Indicates the second line of each line 3 The second time .

Will match the line beginning with the character , Medium bash Change it to false

ssh $i
"sed -i '/^hmsftp/ s#bash#false#' /etc/passwd"

Add... Before each line “123”

sed -i
"s/^/123/g" file name

Add... At the end of each line “abc”

sed -i
"s/$/abc/g" file name

Add... Below the line of matching characters “abc”

sed -i
"/88888/a\abc" file name

Add... Above the line of matching characters “abc”

sed -i
"/88888/i\abc" file name

Add... Under the third line 888888

 sed -i "3a\888888:" /opt/name.txt

=====================

Regular expression applications ：grep

grep
"0*" /etc/passwd  “0” At least appear 0 Time

grep
"00*" /etc/passwd  “0” At least appear 1 Time

grep
"000*" /etc/passwd “0” At least appear 2 Time

grep
[r09] /etc/passwd Anything containing any character in brackets will appear

grep
[^r09] /etc/passwd Anything that does not contain any of the characters in brackets will appear （ Take the opposite ）

grep
"[0-9]\{2\}" /etc/passwd // Matching inclusion 0-9 Numbers , And a line with two digits , Exactly match .

grep
"[0-9]\{2,\}" /etc/passwd  Matching inclusion 0-9 Numbers , Lines with two or more digits

grep
"[0-9]\{1,3\}" /etc/passwd Configuration includes 0-9 Numbers . And there have been 1 Time 2 Time or 3 Every time . Exactly match .

egrep
-v "^$|^#" /etc/vsftpd/vsftpd.conf Put blank lines or # Remove the beginning of the sign .

Egrep
'(xyz)+' passwd

----------- Output related ----------

sed -n
'6p' passwd  Put the second... In the file 6 Line output .

sed -n
'6,8p' passwd Put the second... In the file 6 To the first 8 Line output .

sed -n
'6p;8p' passwd Put the second... In the file 6 And the 8 Line output

sed -n
'p;n' passwd  Output odd lines in the file

sed -n
'n;p' passwd  Output even lines in the file

sed -n
'1,10{n;p}' passwd Put... In the file 1-10 Even rows in rows output

sed -n
'1,10{p;n}' passwd Put... In the file 1-10 Odd rows in rows output

sed -n
'$p' passwd Output the last line of the file .

sed -n
'/root/=' passwd Include... In the file root Line number output of

sed  '5q' passwd Before the output file 5 Exit after line information

-------------- Insert correlation ------------

 sed '/root/i I AM OK' passwd Include in root Insert content before the line of .

 sed '/root/a I AM OK' passwd Include in root Insert content after the line of .

sed
'15a HHHHHHHHH' passwd stay 15 Insert content after line

------- Delete related ------------ Refers to the view , Temporary data deletion , Will not use the original documents     

sed
'1d' passwd Delete first line

sed
'4,7d' passwd Delete 4 To 7 That's ok

 sed '$d' passwd  Delete last line

 sed '/^$/d' passwd Delete blank lines

sed
'/root/d' passwd Delete with root The line of

sed
'/^root/d' passwd Delete with root Beginning line

sed
'/root$/d' passwd Delete with root The line at the end

sed
'/nologin$/!d' bb.txt Delete without nologin The line at the end

------- Replace related ------

sed
's/root//g' passwd Put all the root Replace with empty

sed '1,3s/root//g' passwd hold 1-3 Yes root Replace with empty

sed
'/root/c HHHHH' passwd To contain root Replace the line with the specified character

------ If you want to modify the contents of the file, add a i Parameters ----

sed -i
's/enforcing/disabled/' /etc/sysconfig/selinux

-----------AWK relevant - Processing column -------