Set Hostname

hostname.sh

#!/bin/bash

# Ensure script is run as root
if [ "$(id -u)" -ne 0 ]; then
  echo "❌ Please run this script as root (sudo)."
  exit 1
fi

# Check for hostname argument
if [ -z "$1" ]; then
  echo "Usage: $0 <new-hostname>"
  exit 1
fi

NEW_HOSTNAME="$1"
CURRENT_HOSTNAME=$(hostname)

echo "➡️ Changing hostname from '$CURRENT_HOSTNAME' to '$NEW_HOSTNAME'..."

# Set the hostname
hostnamectl set-hostname "$NEW_HOSTNAME"
echo "$NEW_HOSTNAME" > /etc/hostname

# Update /etc/hosts for 127.0.1.1 (Debian/Ubuntu)
if grep -q "127.0.1.1" /etc/hosts; then
  sed -i "s/127.0.1.1[[:space:]]\+$CURRENT_HOSTNAME/127.0.1.1\t$NEW_HOSTNAME/" /etc/hosts
else
  echo "127.0.1.1   $NEW_HOSTNAME" >> /etc/hosts
fi

# Optional: update 127.0.0.1 line if hostname appears there
if grep -q "127.0.0.1.*$CURRENT_HOSTNAME" /etc/hosts; then
  sed -i "s/\(127.0.0.1.*\)$CURRENT_HOSTNAME/\1$NEW_HOSTNAME/" /etc/hosts
fi

echo "✅ Hostname updated to '$NEW_HOSTNAME'."
reboot