Using systemd-delta (with examples)

Introduction

The systemd-delta command is a useful tool that allows you to find overridden systemd-related configuration files in your system. This can be helpful when troubleshooting issues or understanding the customization done on your system. In this article, we will explore different use cases of the systemd-delta command, along with their corresponding code examples, motivations, explanations, and example outputs.

Use Case 1: Show all overridden configuration files

Code:

systemd-delta

Motivation:

The motivation for using this command is to get a comprehensive list of all the overridden configuration files on the system. This can help identify any customizations made that may conflict with default systemd settings or other configuration files.

Explanation:

By running the systemd-delta command without any additional arguments, it will display a list of all the overridden configuration files. These files are categorized based on the type of override, such as masked, equivalent, redirected, overridden, extended, or unchanged.

Example Output:

etc/systemd/system/myservice.service: overridden
etc/systemd/system/myservice.timer: overridden
etc/systemd/system.conf: overridden
etc/systemd/user.conf: overridden

Use Case 2: Show only files of specific types

Code:

systemd-delta --type overridden,extended

Motivation:

In some cases, you may only be interested in specific types of overridden configuration files. For example, you might want to focus on files that have been overridden or extended to understand customizations made to the system. By using the --type option, you can filter the systemd-delta output to display only the desired file types.

Explanation:

To show only specific types of overridden configuration files, you can use the --type option followed by a comma-separated list of the desired types. Available types include masked, equivalent, redirected, overridden, extended, and unchanged. In the example code above, we are filtering for overridden and extended files.

Example Output:

etc/systemd/system/myservice.service: overridden
etc/systemd/system/myservice.timer: overridden

Use Case 3: Show only files whose path starts with a specified prefix

Code:

systemd-delta /etc/systemd/system

Motivation:

Sometimes, you may want to narrow down the search for overridden configuration files to a specific directory or set of directories. This can be useful when focusing on a particular subset of files, such as system unit files located in /etc/systemd/system. By specifying a prefix, you can limit the search to files that have paths starting with that prefix.

Explanation:

To restrict the search path to files with paths starting with a specific prefix, you can simply provide the prefix as an argument to the systemd-delta command. In the example code above, we are looking for overridden configuration files within the /etc/systemd/system directory.

Example Output:

etc/systemd/system/myservice.service: overridden

Use Case 4: Further restrict the search path by adding a suffix

Code:

systemd-delta /etc/systemd/system/myunits

Motivation:

When searching for overridden configuration files, you may want to narrow down the search even further by adding a suffix to the prefix. This can be helpful when you have multiple directories within the prefix that contain systemd configuration files, and you want to specify a specific subdirectory or file.

Explanation:

To further restrict the search path by adding a suffix, you can provide the prefix (which is optional) followed by the desired suffix as an argument to the systemd-delta command. In the example code above, we are searching for overridden configuration files within the /etc/systemd/system/myunits directory.

Example Output:

etc/systemd/system/myunits/myservice.service: overridden
etc/systemd/system/myunits/myservice.timer: overridden

Conclusion

The systemd-delta command is a powerful tool for finding overridden systemd-related configuration files on your system. By utilizing its different options and arguments, you can narrow down the search and obtain valuable insights into the customizations made to your system. In this article, we explored several use cases of the systemd-delta command, providing code examples, motivations, explanations, and example outputs for each use case.