Originally Posted by alunduil
To edit a system configuration file like that you'll need to escalate to root privileges first. Most distributions let you do this with the `su` command (`su -` on redhat and `sudo su` on ubuntu).
did you mean "su -master.cf"?
i'm beginner in linux. i don't know this commands.
i need this proccess.
1. change chmode master.cf (make editable)
2. edit the master.cf
3. save master.cf