How to use the command cupsctl (with examples)

Cupsctl is a command-line tool used to update or query the configuration of the cupsd.conf file. It allows users to customize the behavior of the Common UNIX Printing System (CUPS) on their server. This article will illustrate various use cases of the cupsctl command.

Use case 1: Display the current configuration values

Code:

cupsctl

Motivation: This use case is useful when you want to see the current configuration values of the CUPS server. It provides an overview of the current settings, which can be helpful for troubleshooting or ensuring that certain options are correctly set.

Explanation: Running the cupsctl command without any arguments will display the current configuration values of the CUPS server.

Example output:

System Default Server: yes
Default server: yes

Use case 2: Display the configuration values of a specific server

Code:

cupsctl -h server[:port]

Motivation: Sometimes, you may have multiple CUPS servers in your network, and you want to retrieve the configuration values of a specific server. This use case allows you to target a specific server and view its configuration.

Explanation: By using the -h (or --host) option followed by the server address and optional port, you can display the configuration values of the specified CUPS server.

Example output:

Server: cups.example.com
Encryption: IfRequested

Use case 3: Enable encryption on the connection to the scheduler

Code:

cupsctl -E

Motivation: Enabling encryption on the CUPS server enhances security by encrypting the connection between the client and the server. This use case allows you to easily enable encryption without manually modifying the cupsd.conf file.

Explanation: The -E (or --encryption) option enables encryption on the connection to the CUPS scheduler. This ensures that all communication between the client and server is encrypted.

Example output: No output is displayed. The command enables encryption on the connection to the scheduler.

Use case 4: Enable or disable debug logging to the error_log file

Code:

cupsctl --debug-logging|--no-debug-logging

Motivation: Debug logging is useful for troubleshooting issues with the CUPS server. Enabling or disabling debug logging allows administrators to control the amount of logging information generated, which can be helpful for diagnosing problems.

Explanation: The --debug-logging option enables debug logging to the error_log file, while the --no-debug-logging option disables it. Debug logs contain detailed information about the CUPS server’s internal operations.

Example output: No output is displayed. The command enables or disables debug logging to the error_log file.

Use case 5: Enable or disable remote administration

Code:

cupsctl --remote-admin|--no-remote-admin

Motivation: Remote administration allows users to manage CUPS servers from remote machines. Enabling or disabling remote administration is important for controlling access to CUPS administrative functions.

Explanation: The --remote-admin option enables remote administration, while the --no-remote-admin option disables it. Enabling remote administration allows users to manage the CUPS server remotely using tools like the CUPS web interface.

Example output: No output is displayed. The command enables or disables remote administration.

Use case 6: Parse the current debug logging state

Code:

cupsctl | grep '^_debug_logging' | awk -F= '{print $2}'

Motivation: Sometimes, you may need to parse the current debug logging state programmatically to determine whether debug logging is enabled or not. This use case provides a command pipeline to extract the relevant information.

Explanation: The cupsctl command is piped into grep with a regular expression ^_debug_logging to filter only the line containing the debug logging state. The output is then piped into awk to extract the second field after the equals sign, which represents the debug logging state.

Example output:

1

Conclusion:

The cupsctl command is a powerful tool for managing and customizing the behavior of the CUPS server. It can be used to display current configuration values, enable encryption, control debug logging, and manage remote administration. Understanding the various use cases and their corresponding commands can help administrators configure and troubleshoot their CUPS servers effectively.