SED/tr etc.. : How to comment out a line that contains “string” in a file?

Question

my file contains lines such as these:

-A INPUT -m state --state NEW -m tcp -p tcp --dport 2000 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport         


        

Answer 1

Through sed,

sed '/ 2001 /s/^/#/' file

Add inline edit -i option to save the changes made.

sed -i '/ 2001 /s/^/#/' file

Example:

$ sed '/ 2001 /s/^/#/' file
-A INPUT -m state --state NEW -m tcp -p tcp --dport 2000 -j ACCEPT
#-A INPUT -m state --state NEW -m tcp -p tcp --dport 2001 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 2002 -j ACCEPT

Answer 2

This awk would do too.

awk '/2001/ {$0="#"$0}1' file
-A INPUT -m state --state NEW -m tcp -p tcp --dport 2000 -j ACCEPT
#-A INPUT -m state --state NEW -m tcp -p tcp --dport 2001 -j ACCEPT
-A INPUT -m state --state NEW -m tcp -p tcp --dport 2002 -j ACCEPT