One of the first things you want to do if you've just installed Raspbian on your Pi is to change the hostname. You can change your hostname by following these steps.

Steps

You can use the 'hostnamectl set-hostname [name]' command, but that does not update /etc/hosts and causes issues with Docker and other networking services. I prefer to update /etc/hostname and /etc/hosts manually.

  1. Change /etc/hostname
sudo nano /etc/hostname

Change raspberrypi to your desired hostname
Hit CTRL+O and then ENTER to Save
Hit CTRL+X to Exit
note: Only use the letters 'a' to 'z' (upper or lower), digits '0' to '9', and the dash '-' for your new hostname.

  1. Change /etc/hosts
sudo nano /etc/hosts

Change raspberrypi to your desired hostname
Hit CTRL+O and then ENTER to Save
Hit CTRL+X to Exit

  1. Reboot
sudo reboot
  1. Check your new hostname
hostname