Is modifying /etc/hostname enough to change the hostname?

Question

I was setting the hostname on my Linux machine with below steps:

1. echo "ABCD" > /etc/hostname
2. hostname -F /etc/hostname
3. Exit from terminal or reboot system
4. Now I can see the new hostname.

Now my question is: What I did here, is that enough for setting the hostname or do I additionally have to change other configuration files, if any?

Answer 1

You don't need to do anything, since you've already changed the hostname by editing /etc/hostname. If you're trying to do something other than change the hostname as the host knows it, please elaborate.

/etc/hosts just lists symbolic names for IPs, so that for example ping localhost does the same as ping 127.0.0.1 if you have a line starting with 127.0.0.1 and localhost somewhere else on the line (whitespace separated). You can of course add abcd to that line, but that has nothing to do with the hostname in /etc/hostname, other than that they coincidentally are the same string. You can't for example enter localhost abcd in the file and expect that to resolve abcd → localhost → 127.0.0.1.

PS: DNS names are not case sensitive, but are conventionally written in lowercase.

Answer 2

As far as I know, you need to change both /etc/hostname and /etc/hosts.