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How To List X Display Names on Ubuntu

Ubuntu 14

In this article, we will delve into how you can list X Display names on Ubuntu. This can be a useful task when managing multiple displays or troubleshooting display-related issues. We will use the command-line interface (CLI) for this task, so a basic understanding of CLI and Ubuntu is beneficial.

Quick Answer

To list X Display names on Ubuntu, you can use the w command in the terminal. Simply type w and press Enter to see a snapshot of the current system status, including the X Display names listed under the "FROM" column. Additionally, you can filter out duplicate display names by combining the w, awk, and sort commands.

What is X Display?

Before we dive into the how-to, let’s briefly discuss what X Display is. In the X Window System, the protocol used by many graphical interfaces in Unix-like operating systems, an X Display is the graphical output on a physically connected or virtually emulated display device. The X Display names are identifiers used by the system to manage and differentiate these output displays.

Listing X Display Names with the w Command

The most straightforward method to list X Display names is by using the w command. This command provides a snapshot of the current system status, including information about the system, logged-in users, and what they are doing.

To use it, open your terminal and simply type w and press Enter. The output will look something like this:

USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
oli tty7 :0 Sat00 5days 4:22m 0.94s gnome-session --session=gnome-fallback
oli pts/4 :0 Sat00 47:09m 0.77s 0.77s /bin/bash
oli pts/6 :0 Wed02 0.00s 0.12s 0.00s w

In this output, the X Display names are listed under the “FROM” column. In this example, the X Display name is :0.

Filtering Unique X Display Names

If you want to filter out duplicate display names, you can use a combination of commands: w, awk, and sort.

w -hs | awk '{print $3}' | sort -u

Here’s what each part of this command does:

  • w -hs: The w command, as mentioned before, shows logged-in users. The -hs option suppresses the header and shortens the output to essential details.
  • awk '{print $3}': The awk command is a powerful text-processing command. Here, it’s used to print only the third column of the output, which contains the X Display names.
  • sort -u: The sort command, as the name suggests, sorts the input. The -u option ensures that the output only contains unique lines.

Running this command will give you a list of unique X Display names.

Using the ps Command for Additional X Displays

The ps command can be used to find X Displays that are not currently logged in. This command provides a snapshot of the current processes in the system.

To list X Displays with the ps command, use the following command:

ps aux | grep X

The ps aux command shows a detailed list of all current processes. The grep X part filters out processes related to X Displays. However, be aware that this method may not show all X Displays, especially those used by login screens.

Conclusion

In this article, we have discussed how to list X Display names on Ubuntu using the w and ps commands. We have also shown how to filter unique display names using a combination of w, awk, and sort commands. These commands are a powerful way to manage and troubleshoot your X Displays. Remember, understanding the output of these commands is key to effectively managing your system’s displays.

What is the difference between X Display and X Window System?

The X Window System is a protocol used by graphical interfaces in Unix-like operating systems, while an X Display is the graphical output on a physically connected or virtually emulated display device. X Display names are identifiers used by the system to manage and differentiate these output displays.

How can I list X Display names on Ubuntu?

To list X Display names on Ubuntu, you can use the w command in the terminal. Simply type w and press Enter. The X Display names will be listed under the "FROM" column in the output.

How can I filter out duplicate X Display names?

You can filter out duplicate X Display names by using a combination of commands: w, awk, and sort. Run the command w -hs | awk '{print $3}' | sort -u in the terminal to get a list of unique X Display names.

Can I use the `ps` command to find additional X Displays?

Yes, you can use the ps command to find additional X Displays. Run the command ps aux | grep X in the terminal to get a list of processes related to X Displays. However, note that this method may not show all X Displays, especially those used by login screens.

Why is it important to understand the output of these commands?

Understanding the output of commands like w and ps is important for effectively managing and troubleshooting X Displays. It allows you to identify which users are logged in, which processes are running, and helps in diagnosing display-related issues.

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