10 + most usable SED Commands for Administrator

1 => To delete any line from any file with sed example.

A: Below command will search and delete httpd line from /etc/rc.local

#sed -i '/httpd/d' /etc/rc.local

B: To make entry in side file with sed example

#sed -i '$ i\\/opt\/lampp\/tomcat\/bin\/startup.sh' /etc/rc.local

#sed -i '$ i\emrepair' /etc/rc.local

Note : Above command will make entry before last line where $i is used for indicate last line

C: This command will make entry in 3^rd line of any file.

#sed -i ' 3i repair' /etc/rc.local

D: Below command will search line and make entry after that

#sed -i '/memory_limit/ a\memory_limit = 1024' /etc/php.ini

E: Below command will search and replace word .

#sed -i 's/FSCKFIX=no/FSCKFIX=yes/' /etc/default/rcS

F: Below command will put # before all the line in a file

#sed -i s/^/#/ filename

G: Remove the 3rd line:

#sed '3d' fileName.txt

H: Remove the line containing the string "awk":

#sed '/awk/d' filename.txt

I: Remove the last line:

#sed '$d' filename.txt

J: Remove all empty lines:

#sed '/^$/d' filename.txt       
#sed '/./!d' filename.txt

K: Remove the line matching by a regular expression (by eliminating one containing digital

characters, at least 1 digit, located at the end of the line):

#sed '/[0-9/][0-9]*$/d' filename.txt

L: Remove the interval between lines 7 and 9:

#sed '7,9d' filename.txt 

M: The same operation as above but replacing the address with parameters:

#sed '/-Start/,/-End/d' filename.txt

N: The above examples are only changed at the display of the file (stdout1= screen).
For permanent changes to the old versions (<4) use a temporary file for GNU sed using the

"-i[suffix]":

#sed -i".bak" '3d' filename.txt

N:  Search 24 character  alfa numeric value in file and replace it 

#sed 's/[[:alnum:]]\{24\}/Nirmal/g'  filename.txt