How to use the command 'xrdb' (with examples)

The ‘xrdb’ command is a resource database utility for Unix-like systems that is used to manage resources in the X Window System. It allows users to load, query, and modify resources in the X server’s resource database.

Use case 1: Start ‘xrdb’ in interactive mode

Code:

xrdb

Motivation: Starting ‘xrdb’ in interactive mode allows users to directly input and modify resource values in the X server’s resource database. This is useful for making real-time changes to the appearance or behavior of X applications.

Explanation: In this use case, the ‘xrdb’ command is called without any arguments, which starts the command in interactive mode. When in interactive mode, ‘xrdb’ launches a shell-like environment where users can enter commands to interact with the resource database.

Example output:

X Windows Resource Database File: /home/user/.Xresources

... (interactive shell)

xrdb> help
Available commands:
!                quit             repeat.last.set  reverse.theme
.                repeat.last.load  revert           write.def
.help            remove           set              write.res
.load            remove.name      setenv           write.xyz
!
... (more interactive shell commands)

Use case 2: Load values from a resource file

Code:

xrdb -load ~/.Xresources

Motivation: Loading values from a resource file is a convenient way to apply a set of style rules or configurations to the X server’s resource database. This allows users to customize the appearance or behavior of X applications consistently.

Explanation: In this use case, the ‘xrdb’ command is called with the ‘-load’ option followed by the path to the resource file (e.g., ~/.Xresources). The ‘-load’ option instructs ‘xrdb’ to read and apply the values from the specified resource file to the resource database.

Example output: (no output if the loading was successful)

Use case 3: Query the resource database and print currently set values

Code:

xrdb -query

Motivation: Querying the resource database and printing currently set values allows users to inspect the current configurations and settings applied to the X server. This is useful for verifying whether the desired changes have been loaded correctly or to troubleshoot any configuration issues.

Explanation: In this use case, the ‘xrdb’ command is called with the ‘-query’ option. This option instructs ‘xrdb’ to query the resource database and print a list of currently set values for the X server.

Example output:

*background:     #000000
*foreground:     #FFFFFF
*focusedBorderColor: #FF0000
*font:           -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
... (more currently set values)

Conclusion:

The ‘xrdb’ command is a powerful utility for managing resources in the X Window System. By understanding and utilizing its various use cases, users can effectively customize the appearance and behavior of X applications to suit their preferences and requirements. Whether it is starting ‘xrdb’ in interactive mode, loading values from a resource file, or querying the resource database, ‘xrdb’ provides the necessary tools for managing resources in the X server.