Changes the hostname on your raspberry pi to what's set in $hostname (variable); can be passed in as a parameter or hard-coded into the script

change_raspberry_pi_hostname.sh

#!/bin/bash

# see LICENSE file on this gist at gist.github.com/codycodes

# Requires root permissions. An easy way to run this script is to simply use "sudo bash change_raspberry_pi_hostname.sh"

# Changes the hostname on your raspberry pi to what's set in $hostname (variable)
# Can be passed in as a parameter by calling this script or set explicitly in this file
# Makes a backup of the hosts file (/etc/hosts.bak)

# set the following variable to the hostname you'd like to use:
hostname='YOUR_CHOSEN_HOSTNAME'

# check if this is running as root
if [[ $EUID > 0 ]]; then echo "Please run this script as root (use sudo)"; exit; fi

if [ $# -eq 0 ]; then
  echo -e -n "No parameters provided, please enter the hostname you'd like to use below:\nhostname: "
  read hostname
elif [$# -gt 1]; then
  echo "incorrect number of arguments. Please run script by using one passed in parameter as hostname or hadcoding the hostname directly into the $hostname variable in the script"
  exit 1;
else
  echo "setting hardcoded hostname in script: $hostname" 
  hostname="$1"
fi

cp /etc/hostname /etc/hostname.bak
echo "$hostname" > /etc/hostname
echo "hostname changed in /etc/hostname to: $(cat /etc/hostname)"
sed -i.bak 's/^127.0.1.1/#127.0.1.1/g' /etc/hosts
echo  "127.0.1.1	$hostname" >> /etc/hosts
echo "successfully added the entry to /etc/hosts! your hosts file now looks like the following:"
cat /etc/hosts
echo "we need to reboot for changes to take effect; press CTRL and the C keys together to cancel; otherwise rebooting in 10 seconds..."
sleep 10
reboot