How to Use the Command 'xwininfo' (with Examples)

The xwininfo command is a powerful tool used in the X Window System to display extensive information about windows presented in a graphical interface. It is exceptionally useful for developers and system administrators who need to gather detailed data regarding windows, such as window id, name, size, position, and more. This tool can assist in debugging, scripting, and managing window-based operations with precision and ease.

Below, we explore various use cases for the xwininfo command, illustrating its versatility and providing examples that cater to a wide range of needs.

Use Case 1: Display a Cursor to Select a Window to Display its Attributes

Code:

xwininfo

Motivation:

You might find yourself needing to examine the details of a specific window on your desktop, but you’re unsure of its exact name or ID. This scenario is quite common when managing multiple windows or when dealing with complex screen setups. Using the xwininfo command without any parameters will provide you with a simple and efficient way to interactively select a window and retrieve its properties. This approach saves time and protects you from the hassle of manually searching for window attributes.

Explanation:

• xwininfo: This is the basic invocation of the command, which when run, puts your cursor in a selection mode. This allows you to click on any window of interest on your desktop, after which xwininfo will print details about the selected window.

Example Output:

xwininfo: Window id: 0x3600001 "Terminal"

  Absolute upper-left X:  2440
  Absolute upper-left Y:  120
  Relative upper-left X:  0
  Relative upper-left Y:  0
  Width: 800
  Height: 600
  Depth: 24
  Visual: 0x24
  Visual Class: TrueColor
  Border width: 1
  Class: InputOutput
  Colormap: 0x20 (installed)
...

This output provides comprehensive data about the window, including its dimensions, class, and visual characteristics.

Use Case 2: Display the Tree of All Windows

Code:

xwininfo -tree -root

Motivation:

Viewing a hierarchical representation of all windows can be exceedingly beneficial when managing a complicated window setup or diagnosing layout issues. Suppose you’re developing a desktop environment or managing multiple virtual desktops. In that case, understanding how windows are nested and layered can inform performance tuning, user interface adjustments, and debugging.

Explanation:

• -tree: This option instructs xwininfo to display a tree-like structure of windows, revealing the parent-child relationships between them.
• -root: Specifies that the tree should start from the root window, which is the top-level window containing all other windows on the current screen.

Example Output:

Root window id: 0x2d7 (the root window) (has no name)
  Parent window id: 0x0 (none)
     2 children:
     0x4400001 (has no name): ("Firefox" "Navigator")  1600x900+0+0  +0+0
     0x3600001 "Terminal": (has no name)  800x600+2440+120  +2440+120

This output provides a snapshot of the window hierarchy, showing how windows are related and nested on the desktop.

Use Case 3: Display the Attributes of a Window with a Specific ID

Code:

xwininfo -id id

Motivation:

When writing scripts or performing tasks that involve specific windows, it’s crucial to have a reliable method for accessing a window’s details using its unique identifier. You might need this information for automation scripts that adjust window properties or for tools that integrate with external APIs, where the window ID is necessary for interacting with or manipulating windows.

Explanation:

• -id: This option allows you to specify the window identifier directly, bypassing the need for a graphical selection and enabling quick access to the window’s attributes.

Example Output:

xwininfo: Window id: 0x4400001 "Firefox"

  Absolute upper-left X:  0
  Absolute upper-left Y:  0
  Relative upper-left X:  0
  Relative upper-left Y:  0
  Width: 1600
  Height: 900
  Depth: 24
  Visual: 0x24
  Visual Class: TrueColor
  Border width: 0
  Class: InputOutput
  Colormap: 0x20 (installed)
...

The output displays the information for the window that matches the specified ID, assisting in targeted management or debugging efforts.

Use Case 4: Display the Attributes of a Window with a Specific Name

Code:

xwininfo -name name

Motivation:

Perhaps you’re developing a window manager or automation solution that interacts with windows by name. In such situations, quickly finding a window’s attributes by its title becomes necessary for efficient operation. This use case would cater to developers or power users who need to script interactions with windows that aren’t easily identifiable by ID alone.

Explanation:

• -name: This argument specifies the window title, allowing you to fetch and display its attributes based on its name.

Example Output:

xwininfo: Window id: 0x3600001 "Terminal"

  Absolute upper-left X:  2440
  Absolute upper-left Y:  120
  Relative upper-left X:  0
  Relative upper-left Y:  0
  Width: 800
  Height: 600
  Depth: 24
  Visual: 0x24
  Visual Class: TrueColor
  Border width: 1
  Class: InputOutput
  Colormap: 0x20 (installed)
...

This would return the attributes of the window matching the specified name, speeding up workflows that require name-to-attribute mapping.

Use Case 5: Display the ID of a Window Searching by Name

Code:

xwininfo -tree -root | grep keyword | head -1 | perl -ne 'print $1 if /(0x[\da-f]+)/ig;'

Motivation:

Accurately retrieving the ID of a window based on part of its name can be invaluable in scripting and automation. If you’re setting up a script that targets a specific application window but only know part of its name or title, using this method allows for efficient window identification via pattern matching, thereby streamlining automated tasks.

Explanation:

• -tree -root: This displays the entire tree of windows, starting from the root.
• grep keyword: Filters the list to find windows containing the specified keyword in their name.
• head -1: Returns the first match, assuming you want only the first relevant window.
• perl -ne 'print $1 if /(0x[\da-f]+)/ig;': Extracts and prints the hexadecimal window ID from the filtered output.

Example Output:

0x4400001

This output shows the window ID of the first window matching the specified keyword, making it easy to further interact with this window in a script or automation routine.

Conclusion:

The xwininfo command is an indispensable tool for anyone working with the X Window System, providing comprehensive solutions for windows management tasks. By utilizing its various options, users can easily retrieve information, navigate window hierarchies, and integrate window details into scripts, enhancing overall productivity and system insight. Whether you’re a developer, a system administrator, or a power user, mastering xwininfo garners precise control over your graphical environment.