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Safety

filerepack is designed to leave the source file untouched until a candidate is verified and actually smaller.

Write path​

Rewrites go to a temp file, are verified, then os.replaced onto the original. A missing 7zz/7z leaves the source archive untouched. Packers must not unlink user files before a successful rewrite.

Discard if not smaller​

Output that is not smaller than the original is discarded unless --allow-grow. --min-savings PCT keeps the result only if savings are at least that percent.

Backups and output directory​

filerepack repack contract.docx --backup
filerepack repack contract.docx --backup-dir ./backups
filerepack repack contract.docx --output-dir ./out

--dryrun measures savings and does not modify files.

Archive extract limits​

--max-extract-size skips archive extract if uncompressed size exceeds the limit (0 disables). The default is 8 GB, and also 100× the archive size, so a tiny zip bomb is not fully expanded.

Files that stay untouched​

These are never extracted and rewritten:

  • Signed installers: deb, rpm, pkg, dmg
  • Disc/library archives 7-Zip cannot create: iso, cpio, ar / a / lib
  • OpenType .otf fonts (ZIP ODF templates with that extension are packed)
  • Encrypted or digitally signed PDFs skip pikepdf stream replacement; lossless qpdf may still run
  • DICOM instances that are signed, non-image, or already compressed