Ubuntu Hostname Change Guide

This document provides a clear, structured, and professional guide explaining how to change the hostname on Ubuntu. It is written for developers, system administrators, or anyone maintaining Linux systems.

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Introduction

A hostname is the unique identifier assigned to a machine on a network. It appears in the terminal prompt, plays a role in local and remote communication, and is used by several system services. Keeping the hostname consistent and meaningful is good practice for system organization and maintenance.

This guide describes two methods for changing the hostname on Ubuntu:

• the recommended method using hostnamectl
• the manual method using configuration files

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Method 1 — Recommended: Using hostnamectl

Ubuntu systems that use systemd provide the hostnamectl tool, which is the safest and most consistent way to modify the hostname.

1. Check the current hostname

Use the following command to inspect the active hostname and related system information:

hostnamectl

2. Set the new hostname

Replace NEW_HOSTNAME with the desired hostname:

sudo hostnamectl set-hostname NEW_HOSTNAME

This updates the static, pretty, and transient hostnames automatically.

3. Update /etc/hosts

To ensure proper local name resolution, manually update the hosts file:

sudo nano /etc/hosts

Look for a line similar to:

127.0.1.1    current-hostname

Replace it with:

127.0.1.1    NEW_HOSTNAME

Save the file and exit:

• CTRL + O → ENTER
• CTRL + X

4. Reboot the system

A reboot ensures all services load the new hostname:

sudo reboot

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Method 2 — Manual Editing (Alternative)

This method directly edits configuration files. It works, but requires more caution.

1. Modify /etc/hostname

sudo nano /etc/hostname

Replace the existing hostname with the new one.

2. Update /etc/hosts (same as in Method 1)

sudo nano /etc/hosts

Update the 127.0.1.1 entry to reflect the new hostname.

3. Reboot

sudo reboot

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Notes and Best Practices

• Hostnames should contain only lowercase letters, digits, and hyphens.
• Avoid spaces or special characters.
• Always update /etc/hosts to prevent name resolution issues.
• Most system services will automatically pick up the new hostname after reboot.

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Verify the Change

After the system restarts, verify the hostname:

hostnamectl

hostname

Both commands should return the updated hostname.

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Additional Recommendations

• Choose meaningful hostnames when working with multiple servers or virtual machines (e.g., data-node01, workstation-ubuntu, analysis-server).
• If the machine participates in a domain or uses services like SSH, consider verifying the configuration after the change.

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Conclusion

Changing the hostname on Ubuntu is straightforward when using hostnamectl. Updating both hostname and /etc/hosts ensures smooth system behavior and proper resolution. This guide provides a reliable procedure suitable for production environments, educational material, and documentation within a GitHub repository.