ucfr

ucfr [options]

-v
    Verbose mode. Provides more detailed output.

-n
    Dry-run mode. Simulates the update process without actually modifying any files.

-y
    Answer 'yes' to all prompts automatically. Use with extreme caution, as it can overwrite configuration files without user interaction.

-q
    Answer 'no' to all prompts automatically. Will keep existing configs in place.


    The path to the existing configuration file to be updated. This is usually listed in the package's conffiles.


    The path to the new configuration file provided by the package.

The `ucfr` (Update Configuration File Replacement) command is a Debian-specific utility designed to manage configuration files during package upgrades. It intelligently handles situations where the configuration file in a package has been modified by the administrator or user. `ucfr` compares the currently installed configuration file, the new configuration file provided by the package, and the original configuration file that was installed when the package was initially installed. It then prompts the user to choose whether to keep their modified version, install the new version, or view a diff of the changes. The command ensures that important configurations are not automatically overwritten, preventing potential system malfunctions. `ucfr` is typically called by package maintainer scripts during install/upgrade procedures of deb packages. The program uses dpkg's conffiles mechanism to find configuration files to manage. `ucfr` has associated helpers (`ucf`, `ucfq`, `ucfmerge`) for more specific management tasks. It is a crucial tool for maintaining system integrity during package updates on Debian-based systems.

Using `-y` can lead to unintended overwrites of custom configurations. Use it with great caution and only when you are absolutely sure you want to accept all changes. `ucfr` heavily relies on dpkg's conffiles information. If a file is not correctly declared as a conffile, `ucfr` will not manage it.

ucfr returns 0 on success. Non-zero exit codes indicate errors, such as file not found or user intervention needed (e.g., user refused to overwrite a file). The specific exit codes are detailed in the ucfr man page. Understanding the exit status is important when using `ucfr` in automated scripts.

`ucfr` was developed as part of the Debian project to address the complex issue of configuration file management during package upgrades. Prior to `ucfr`, administrators often faced the risk of losing their custom configurations when a package upgrade replaced the existing configuration file with the package's default version. `ucfr` was designed to provide a safe and user-friendly way to resolve conflicts and ensure that important settings are preserved. The development involved careful consideration of various scenarios, including modified configurations, removed options, and completely rewritten configuration files. It is now an integral part of the Debian packaging system and is used in countless package updates across Debian-based distributions.

ucf(1), ucfq(1), ucfmerge(1), dpkg(1)