Add comments and set the hostname when given input

bootstrap.sh

@@ -1,15 +1,19 @@
 #!/bin/bash
 
+# Root required
 if [ $EUID -ne 0 ]; then
   echo "You must run this script as root"
   exit 1
 fi
 
+# Get current date, hostname, create a temporary directory,
+# and set the location to the remote repository
 DATE=$(date '+%Y%m%d')
 TMP_DIR=$(mktemp -d)
 CUR_HOSTNAME=$(hostname)
 GIT_LOC="https://github.com/krislamo/bootstrap.git"
 
+# Get user input for hostname and IP
 echo "Enter name server's new hostname:"
 read NEW_HOSTNAME
 
@@ -24,22 +28,26 @@ if [ ! -z "$STATIC_IP" ]; then
   echo "Gateway set to $GATEWAY_IP"
 fi
 
+# Remove CD sources
 cp /etc/apt/sources.list /etc/apt/sources.list.$DATE
 sed -i '/deb cdrom/d' /etc/apt/sources.list
 
+# Upgrade software
 apt-get update -y
 apt-get upgrade -y
-apt-get install git -y
 
+# Install git, clone this repo, and navigate to it
+apt-get install git -y
 cd $TMP_DIR
 git clone $GIT_LOC
 cd bootstrap
 
+# Install personal SSH keys under root and install the OpenSSH server
 mkdir -p /root/.ssh/
 cp --update authorized_keys /root/.ssh/authorized_keys
 apt-get install openssh-server -y
 
-# If STATIC_IP var was set, backup interfaces and set static IP
+# If STATIC_IP is set, backup interfaces and configure static IP
 if [ ! -z "$STATIC_IP" ]; then
   cp /etc/network/interfaces /etc/network/interfaces.$DATE
   sed -i "s/dhcp/static/g" /etc/network/interfaces
@@ -49,8 +57,11 @@ if [ ! -z "$STATIC_IP" ]; then
   fi
 fi
 
-hostnamectl set-hostname $NEW_HOSTNAME
-cp /etc/hosts /etc/hosts.$DATE
-sed -i "s/$CUR_HOSTNAME/$NEW_HOSTNAME/g" /etc/hosts
-read -p "Press [enter] to restart this machine"
-/sbin/shutdown -r now
+# If NEW_HOSTNAME is set, configure new hostname and backup /etc/hosts
+if [ ! -z "$NEW_HOSTNAME" ]; then
+  hostnamectl set-hostname $NEW_HOSTNAME
+  cp /etc/hosts /etc/hosts.$DATE
+  sed -i "s/$CUR_HOSTNAME/$NEW_HOSTNAME/g" /etc/hosts
+  read -p "Press [enter] to restart this machine"
+  /sbin/shutdown -r now
+fi