Era : I've closely examinded the configuration file and there are some 10 or 11 lines to be changed or modified.. and I know exactly which ones .. Although your approach is good and maybe better as well, just because I don't know how to do it I find line manipulation easier..thank you for your answer

penchal_boddu
how exactly should I use a option of sed ... is it like this

Code:

sed -a '980s/anything/anything/' filename.

if yes will this create a line if it reaches the end of the file or if the line is existing will it modify it ? Thank you