xlsclients

List clients on the default display

$ xlsclients

$ xlsclients -a

$ xlsclients -l

$ xlsclients -m [max_command_length]

$ xlsclients -display :[display_number]

$ xlsclients -display [remote_host]:0

$ xlsclients -version

xlsclients [-display display] [-l] [-a] [-u] [-m] [-V]

-display display
    Specifies the X server to connect to. If not specified, the value of the DISPLAY environment variable is used.

-l
    Displays output in a long format. This includes the window name, icon name, and the hostname where the client is running.

-a
    Lists all clients, including those usually hidden, such as internal server clients or clients that don't own any top-level windows.

-u
    Includes clients even if their top-level window is currently unmapped. By default, xlsclients only shows clients whose top-level windows are mapped.

-m
    Shows information specifically about the window manager client. This is useful for identifying the active window manager.

-V
    Prints the xlsclients version number to standard output and then exits.

xlsclients is a command-line utility used to list applications connected to an X Window System display. It queries the X server to identify active clients, providing information about each one, such as its resource ID and, when available, its window name and hostname.

This tool is particularly useful for system administrators and developers to diagnose issues, understand which applications are consuming display resources, or verify if specific X clients are running as expected. It can display information in a concise format or provide more detailed output depending on the options used. xlsclients helps in gaining insight into the dynamic state of an X server's client connections.

xlsclients relies on the X server to provide client information, which may be limited or vary in detail depending on the X server implementation and version. It primarily lists connections to the X server rather than all processes on the system that might interact with X. It does not provide performance metrics like CPU or memory usage; other system monitoring tools are required for such details.

xlsclients is a fundamental utility within the X Window System's core distribution. It has been a part of the standard x11-utils or xorg-x11-apps packages for many years, maintaining its essential purpose of listing X clients without significant changes to its core functionality or options over time, reflecting its stable and specialized role in X system administration.

xprop(1), xwininfo(1), xdpyinfo(1), xset(1), ps(1)