Can unrar Generate MD5 Checksum Files?

The command-line tool unrar cannot natively generate external checksum files, such as .md5 or .sha256, alongside extracted files. While unrar includes built-in integrity verification mechanisms to ensure extracted files are not corrupt, creating standalone digest files requires pairing unrar with external hashing utilities. This guide outlines how unrar handles checksum verification internally and provides practical shell commands to automatically generate checksum files immediately after extraction on Linux, macOS, and Windows.

How unrar Handles File Integrity

RAR archives contain internal checksums for every compressed file. Depending on the archive version, WinRAR and rar embed either CRC32 hashes (RAR4 format) or BLAKE2sp hashes (RAR5 format) directly within the archive metadata.

When you run an extraction command such as unrar x archive.rar or a test command like unrar t archive.rar, the utility automatically calculates the checksum of the unpacked data and compares it against the stored value. If a mismatch occurs, unrar flags a checksum error. However, unrar lacks any command-line switch or configuration setting to export these internal hashes into an external hash list or to calculate third-party digests like MD5 or SHA-256 during extraction.

Generating Checksum Files on Linux and macOS

To create a checksum file alongside your unpacked data, you can chain unrar with standard Unix hashing tools such as md5sum or sha256sum.

To extract into a specific folder and immediately generate an MD5 checksum file for all extracted contents:

unrar x archive.rar output_dir/ && cd output_dir && md5sum * > checksums.md5

If the archive contains subdirectories and you need recursive hashing, use find:

unrar x archive.rar output_dir/ && cd output_dir && find . -type f -not -name "checksums.md5" -exec md5sum {} + > checksums.md5

To create SHA-256 files instead, substitute md5sum with sha256sum.

Generating Checksum Files on Windows (PowerShell)

On Windows systems, you can achieve the same automated workflow using PowerShell alongside the unrar.exe executable and the Get-FileHash cmdlet.

To extract the archive and generate an MD5 checksum file:

unrar.exe x archive.rar output_dir\
Get-ChildItem -Path output_dir -File -Recurse | Get-FileHash -Algorithm MD5 | Format-Table Hash, Path > output_dir\checksums.md5

For a standard SHA-256 hash list, replace -Algorithm MD5 with -Algorithm SHA256.

Conclusion

While unrar guarantees that extracted files match the state in which they were originally archived via its internal CRC32 or BLAKE2 algorithms, it does not support generating external checksum files. The standard and most reliable practice is to chain the extraction command with native operating system hashing tools.