When you SSH into an AWS EC2 instance, you'll typically see a prompt like this:

[ec2-user@ip-10-128-80-10 ~]$

The ip-10-128-80-10 portion is the internal hostname automatically assigned by AWS. For developers managing multiple instances, this isn't the most user-friendly or memorable format.

The most robust solution is to change the system hostname itself:

sudo hostnamectl set-hostname us1

Verify the change took effect:

hostnamectl

For temporary changes or more control over the prompt format, modify the PS1 variable in ~/.bashrc:

# Edit ~/.bashrc
nano ~/.bashrc

# Add or modify this line
export PS1="[\\u@us1 \\W]\\$ "

# Apply changes
source ~/.bashrc

For multiple instances, you might want to set hostnames based on instance tags:

#!/bin/bash
INSTANCE_ID=$(curl -s http://169.254.169.254/latest/meta-data/instance-id)
REGION=$(curl -s http://169.254.169.254/latest/meta-data/placement/region)
HOSTNAME=$(aws ec2 describe-tags \
  --filters "Name=resource-id,Values=$INSTANCE_ID" "Name=key,Values=Name" \
  --region $REGION --output text | cut -f5)

sudo hostnamectl set-hostname "$HOSTNAME"

On older systems, you may need to edit additional files:

# Edit /etc/hosts
127.0.0.1   localhost us1

# Edit /etc/sysconfig/network (on RHEL/CentOS)
HOSTNAME=us1

After making any changes, verify with:

hostname
echo $PS1

You should now see your custom hostname in the prompt:

[ec2-user@us1 ~]$

---

When you SSH into an Amazon EC2 instance, you'll typically see a prompt like this:

[ec2-user@ip-10-128-80-10 ~]$

This format follows the standard Linux convention of [username@hostname working-directory], where the hostname defaults to the internal IP address in EC2 instances.

Customizing the hostname offers several advantages:

• Easier identification when managing multiple instances
• Better organization in team environments
• More professional appearance in screenshots/demos

For a session-specific change (won't persist after reboot):

sudo hostname us1
exec bash

The exec bash command refreshes your shell to display the new hostname.

For a persistent change across reboots, edit these files:

On Modern Linux (systemd)

sudo hostnamectl set-hostname us1

On Older Systems

Edit /etc/hostname:

sudo nano /etc/hostname
# Replace contents with just your desired hostname:
us1

Then modify /etc/hosts:

127.0.0.1   localhost localhost.localdomain us1
::1         localhost localhost.localdomain us1

Check the current hostname with:

hostname
hostnamectl status

For advanced prompt customization, edit ~/.bashrc:

PS1='[\u@\h \W]\$ '
# Or for color:
PS1='$$\e[32m$$[\u@\h \W]\$$$\e[0m$$ '

• Avoid using dots in hostnames (us1 instead of us1.example.com)
• Changes might affect some AWS services that rely on the original hostname
• Always test in a staging environment first

For new instances, set the hostname in user-data:

#cloud-config
hostname: us1
fqdn: us1.local