How to Extract RAR to Stdout Using Unrar

Extracting files directly to standard output (stdout) allows you to process compressed data in memory, stream it to other utilities, or redirect it without writing temporary files to disk. The standard non-free unrar utility fully supports this behavior using the p (print) command combined with flags that suppress extraneous logging messages.

The Basic Command

To send the contents of a file inside an archive directly to stdout, use the p command:

unrar p archive.rar file_inside.txt

If you do not specify an individual file name, unrar will dump the contents of every file in the archive sequentially into the stdout stream.

Suppressing Console Messages

By default, unrar outputs diagnostic banners, version details, and extraction status messages to the console alongside the file content. If you are piping binary data or redirecting output to a new file, these banners will corrupt the stream.

To disable all informational messages and output only the raw file data, include the -inul (inquire null / disable messages) switch:

unrar p -inul archive.rar target_file.bin > extracted_file.bin

Piping to Other Commands

Streaming to standard output is particularly useful for piping extracted content directly into other command-line tools without intermediate disk storage:

  • Inspect text files with a pager:

    unrar p -inul archive.rar log.txt | less

  • Search inside a compressed file:

    unrar p -inul archive.rar data.csv | grep "search_term"

  • Compute a checksum without extraction:

    unrar p -inul archive.rar disc.iso | sha256sum

Handling Password-Protected Archives

If the archive requires a password, supply it via the -p<password> switch directly adjacent to the flag without a space, ensuring the process remains fully non-interactive:

unrar p -inul -pSecretPassword archive.rar file.txt

Alternative: Using 7-Zip

If unrar is unavailable on your system, p7zip (via the 7z command) offers the exact same capability using the -so (standard output) switch:

7z e -so archive.rar target_file.bin > extracted_file.bin