If you are a developer, you may have encountered the ‘No Display Name and No Display Environment Variable’ error. This error is typically encountered when trying to run graphical applications from a terminal or over SSH. It can be quite frustrating, especially when you need to get your work done quickly.
Fortunately, this error is fixable, and in this guide, we will take you through the steps necessary to fix it. We will also provide you with some valuable information and answer some frequently asked questions.
What Causes the ‘No Display Name and No Display Environment Variable’ Error?
The ‘No Display Name and No Display Environment Variable’ error occurs when your system is unable to locate the X server display. This can happen due to several reasons, including:
- SSH connection issues
- Missing X server packages
- Configuration issues
- Incorrect environment variables
How to Fix the ‘No Display Name and No Display Environment Variable’ Error
To fix this error, follow the steps below:
Step 1: Check Your SSH Connection
Ensure that your SSH connection is properly established. You can do this by running the command below:
ssh -X user@remotehost
Step 2: Install the X Server Packages
If the X server packages are missing, you may encounter this error. To install the packages, run the command below:
sudo apt-get install xorg xauth x11-apps
Step 3: Configure Your SSH
Edit the SSH configuration file (/etc/ssh/sshd_config) to enable X11 forwarding. Uncomment the following line:
X11Forwarding yes
Step 4: Restart the SSH Service
Restart the SSH service to apply the changes made to the configuration file. Run the command below:
sudo service ssh restart
Step 5: Set Your Display Environment Variable
Set the DISPLAY environment variable to the IP address of your local machine. Run the command below:
export DISPLAY=local_ip_address:0.0
Frequently Asked Questions
Q1. What is X server?
X server is a software that enables graphical user interfaces for Unix and Unix-like operating systems.
Q2. Can I use X11 forwarding over SSH on Windows?
Yes, you can use X11 forwarding over SSH on Windows. You will need to install an X server application such as Xming or VcXsrv.
Q3. How do I check if X server is running?
You can check if X server is running by running the command below:
ps aux | grep Xorg
Q4. What is the DISPLAY environment variable?
The DISPLAY environment variable is used to specify the display server that graphical applications should use.
Q5. Can I set the DISPLAY environment variable permanently?
Yes, you can set the DISPLAY environment variable permanently by adding the following line to your .bashrc file:
export DISPLAY=local_ip_address:0.0