How To Change Hostname In Linux Permanently Command Line

Hostnames in Linux

The distinctive name given to a computer on a network is called a hostname in Linux. Rather of utilizing complicated IP addresses, it helps identify a system in a way that is legible by humans. A system’s hostname makes it easy for administrators and apps to identify and connect to it, regardless of whether it’s a personal laptop, business server, or cloud instance.

What is a Hostname?

A hostname is a label given to a Linux system so it can be identified within a network. Instead of remembering an IP address like 192.168.1.20, users can refer to the system by a name such as webserver, db01, or linux-client.

In simple terms, a hostname acts like a computer’s identity.

Example:

</> bash

user@server01:~$

Here, server01 is the hostname.

How Hostname Works Internally

Step 1: Stored in System Configuration

Linux stores the hostname in:

</> code

/etc/hostname

This file contains a single line:

</> code

server01

Step 2: Loaded During Boot

When the system boots:

1. The Linux kernel starts.
2. The init system (usually systemd) reads /etc/hostname.
3. The hostname is set in the kernel using the sethostname() system call.
4. The hostname becomes active.

You can check it using:

</> bash

hostname

or

</> bash

hostnamectl

Step 3: Stored in Kernel Memory

After boot:

• The hostname is stored in kernel memory.
• It remains active until reboot.
• Temporary changes affect only runtime unless saved.

How Hostname Works in Networking

When your system communicates:

1. The hostname is attached to network services (SSH, web server, etc.).
2. Other systems resolve it using:
   • /etc/hosts
   • DNS server

Example /etc/hosts:

</> code

127.0.0.1   localhost
192.168.1.10   server01

If DNS is configured, hostname → IP resolution happens automatically.

Types of Hostnames in Linux

Linux systems support three main hostname types:

1. Static Hostname

• Stored in /etc/hostname
• Persistent across reboots
• Set manually by the administrator
• Used for servers and production systems

Example:

cpp

hostnamectl set-hostname server01

2. Transient Hostname

• Assigned temporarily
• Often set automatically by DHCP
• Lost after reboot
• Common in dynamic environments

3. Pretty Hostname

• Human-friendly version
• Can include spaces and special characters
• Used for display purposes

Example:

sql

hostnamectl set-hostname "Development Server" --pretty

Managing Hostnames

The modern way to manage these names is via the hostnamectl command.

Goal	Command
View Hostnames	hostnamectl status
Change Static Name	sudo hostnamectl set-hostname [new-name]
Set Pretty Name	sudo hostnamectl set-hostname "[name]" --pretty
Check Local Mapping	cat /etc/hosts

Functions in the Operating System

• Identification: Distinguishes the machine in log files (/var/log/syslog) so administrators know which server generated an error.
• Network Communication: Allows services like SSH, Mail servers, and Web servers to identify the source and destination of data.
• Shell Prompting: Provides context to the user in the Command Line Interface (CLI).
• Security: Used in SSL/TLS certificates to verify that the server you are connecting to is actually who it claims to be.

Benefits of Hostname

• Friendly to Humans: More memorable than IP addresses.
• Adaptable: While the hostname stays the same, IP addresses can change.
• Expandable: Beneficial in settings with hundreds of servers at huge enterprises.
• Facilitates Automation: Hostnames are necessary for configuration management tools and scripts.
• Enhances Network Structure: Makes infrastructure readable and organized.

Drawbacks of hostnames

• Reliance on DNS: Hostname resolution may not work if DNS fails.
• Problems with Misconfiguration: Network issues may result from improper hostname configuration.
• Name Duplication: Conflicts may arise if two systems have the same hostname.
• Exposure to Security: System roles (like db-server) may be disclosed by public hostnames.

Hostname vs IP Address

Feature	Hostname	IP Address
Format	Alphanumeric (server-01)	Numeric (192.168.1.5)
Memorability	High	Low
Consistency	Permanent (usually)	Can change (DHCP)
Use Case	Human interaction	Machine routing

How to change Hostname in linux

Changing a hostname in Linux is a straightforward process, but the “correct” way depends on whether you want the change to be temporary or permanent. On modern systems (Ubuntu, Debian, Fedora, CentOS/RHEL 7+), the hostnamectl command is the standard tool.

The Modern Way (Permanent)

The hostnamectl command is part of systemd. It updates the hostname in the kernel and ensures it stays changed after a reboot by automatically editing the necessary configuration files.

The Command:

bash

sudo hostnamectl set-hostname <new-hostname>

Example: If you want to rename your machine to “jupiter-server”:

bash

sudo hostnamectl set-hostname jupiter-server

Verify the Change

Run the status command to see the new static hostname and system details:

bash

hostnamectl status

Also read about CentOS Features And Differences Between CentOS vs Ubuntu

The Traditional/Manual Way

On older distributions or if you prefer manual editing, you must update two specific files to ensure the change survives a reboot.

Step A: Edit /etc/hostname

Open the file and replace the old name with your new name.

bash

sudo nano /etc/hostname

Step B: Edit /etc/hosts

This is a critical step. If you don’t update this file, some applications (like sudo) may hang or throw errors because they can’t “resolve” the new name back to the local machine.

bash

sudo nano /etc/hosts

Find the line that looks like this: 127.0.1.1 old-hostname Change it to: 127.0.1.1 new-hostname

The Temporary Way (Instant)

If you only need to change the hostname for the current session (it will revert back to the old one after a restart), use the hostname command:

bash

sudo hostname <new-name>

Setting a “Pretty” Hostname

Modern Linux allows for a “Pretty” hostname that supports spaces, capital letters, and special characters (used for display in file managers or discovery services).

bash

sudo hostnamectl set-hostname "Gerrit's Main Workstation" --pretty

• Allowed Characters: Ideally, hostnames should only consist of hyphens (-), integers (0–9), and letters (a–z). A hyphen should not be used at the beginning or end of them.

• Case Sensitivity: Although most hostnames are case-insensitive, Linux uses lowercase as a universal standard to prevent confusion.

• Terminal Refresh: Your terminal prompt may remain display the previous hostname even after you have changed it. To view the update, just exit the terminal and launch a new one, or use exec bash.

Also read about Linux Networking Commands Interview Questions And Answers