Unrar Update Files Only If Newer

This guide explains how to use the unrar command-line utility to extract files from a RAR archive while only overwriting existing files in a destination directory if the archived versions are newer. Utilizing the built-in update and freshen switches allows you to synchronize folders, save processing time, and prevent newer files from being overwritten by older versions.

The Basic Command

To extract files and only replace existing ones if the archive contains a newer version, use the x command with the -u (update) switch:

unrar x -u archive.rar /path/to/destination/

Command Breakdown

• x: Extracts files while preserving the original folder structure. (If you prefer to extract all files into a single flat directory without subfolders, use e instead of x).
• -u: Enables update mode. It extracts files that do not exist in the destination directory and updates existing files only if the archived copy has a newer modification date.
• archive.rar: The path to the RAR file you want to extract.
• /path/to/destination/: The target directory where the files will be placed.

Update (-u) vs. Freshen (-f)

Depending on your requirements, unrar provides two different flags for date-based extraction:

1. Update Switch (-u): Extracts files if they do not exist in the destination directory or if they are newer than the existing files.

   unrar x -u archive.rar

2. Freshen Switch (-f): Only updates files that already exist in the target directory and are older than the archived copies. Any files in the archive that are not present in the target directory will be skipped.

   unrar x -f archive.rar

Running Non-Interactively

By default, unrar may prompt you for confirmation before performing operations. To automate the process in scripts or run it without manual prompts, combine the update switch with the assume-yes flag (-y):

unrar x -u -y archive.rar /path/to/destination/

This ensures that only newer or missing files are extracted automatically without user intervention.