====== bitrot ====== Detects bit rotten files on the hard drive to save your precious photo and music collection from slow decay. Usage ----- Go to the desired directory and simply invoke:: $ bitrot This will start digging through your directory structure recursively indexing all files found. The index is stored in a ``.bitrot.db`` file which is a SQLite 3 database. Next time you run ``bitrot`` it will add new files and update the index for files with a changed modification date. Most importantly however, it will report all errors, e.g. files that changed on the hard drive but still have the same modification date. All paths stored in ``.bitrot.db`` are relative so it's safe to rescan a folder after moving it to another drive. Just remember to move it in a way that doesn't touch modification dates. Otherwise the checksum database is useless. Performance ----------- Obviously depends on how fast the underlying drive is. Historically the script was single-threaded because back in 2013 checksum calculations on a single core still outran typical drives, including the mobile SSDs of the day. In 2020 this is no longer the case so the script now uses a process pool to calculate SHA1 hashes and perform `stat()` calls. No rigorous performance tests have been done. Scanning a ~1000 file directory totalling ~5 GB takes 2.2s on a 2018 MacBook Pro 15" with a AP0512M SSD. Back in 2013, that same feat on a 2015 MacBook Air with a SM0256G SSD took over 20 seconds. On that same 2018 MacBook Pro 15", scanning a 60+ GB music library takes 24 seconds. Back in 2013, with a typical 5400 RPM laptop hard drive it took around 15 minutes. How times have changed! Tests ----- There's a simple but comprehensive test scenario using `BATS <https://github.com/sstephenson/bats>`. Run the file in the `tests` directory to run it. Change Log ---------- 1.0.0 ~~~~~ * significantly sped up execution on solid state drives by using a process pool executor to calculate SHA1 hashes and perform `stat()` calls; use `-w1` if your runs on slow magnetic drives were negatively affected by this change * sped up execution by pre-loading all SQLite-stored hashes to memory and doing comparisons using Python sets * all UTF-8 filenames are now normalized to NFKD in the database to enable cross-operating system checks * the SQLite database is now vacuumed to minimize its size * bugfix: additional Python 3 fixes when Unicode names were encountered 0.9.2 ~~~~~ * bugfix: one place in the code incorrectly hardcoded UTF-8 as the filesystem encoding 0.9.1 ~~~~~ * bugfix: print the path that failed to decode with FSENCODING * bugfix: when using -q, don't hide warnings about files that can't be statted or read * bugfix: -s is no longer broken on Python 3 0.9.0 ~~~~~ * bugfix: bitrot.db checksum checking messages now obey --quiet * Python 3 compatibility 0.8.0 ~~~~~ * bitrot now keeps track of its own database's bitrot by storing a checksum of .bitrot.db in .bitrot.sha512 * bugfix: now properly uses the filesystem encoding to decode file names for use with the .bitrotdb database. Report and original patch by pallinger. 0.7.1 ~~~~~ * bugfix: SHA1 computation now works correctly on Windows; previously opened files in text-mode. This fix will change hashes of files containing some specific bytes like 0x1A. 0.7.0 ~~~~~ * when a file changes or is renamed, the timestamp of the last check is updated, too * bugfix: files that disappeared during the run are now properly ignored * bugfix: files that are locked or with otherwise denied access are skipped. If they were read before, they will be considered "missing" in the report. * bugfix: if there are multiple files with the same content in the scanned directory tree, renames are now handled properly for them * refactored some horrible code to be a little less horrible 0.6.0 ~~~~~ * more control over performance with ``--commit-interval`` and ``--chunk-size`` command-line arguments * bugfix: symbolic links are now properly skipped (or can be followed if ``--follow-links`` is passed) * bugfix: files that cannot be opened are now gracefully skipped * bugfix: fixed a rare division by zero when run in an empty directory 0.5.1 ~~~~~ * bugfix: warn about test mode only in test mode 0.5.0 ~~~~~ * ``--test`` command-line argument for testing the state without updating the database on disk (works for testing databases you don't have write access to) * size of the data read is reported upon finish * minor performance updates 0.4.0 ~~~~~ * renames are now reported as such * all non-regular files (e.g. symbolic links, pipes, sockets) are now skipped * progress presented in percentage 0.3.0 ~~~~~ * ``--sum`` command-line argument for easy comparison of multiple databases 0.2.1 ~~~~~ * fixed regression from 0.2.0 where new files caused a ``KeyError`` exception 0.2.0 ~~~~~ * ``--verbose`` and ``--quiet`` command-line arguments * if a file is no longer there, its entry is removed from the database 0.1.0 ~~~~~ * First published version. Authors ------- Glued together by `Łukasz Langa <mailto:lukasz@langa.pl>`_. Multiple improvements by `Ben Shepherd <mailto:bjashepherd@gmail.com>`_, `Jean-Louis Fuchs <mailto:ganwell@fangorn.ch>`_, `Marcus Linderoth <marcus@thingsquare.com>`_, `p1r473 <mailto:subwayjared@gmail.com>`_, `Peter Hofmann <mailto:scm@uninformativ.de>`_, `Phil Lundrigan <mailto:philipbl@cs.utah.edu>`_, `Reid Williams <rwilliams@ideo.com>`_, `Stan Senotrusov <senotrusov@gmail.com>`_, `Yang Zhang <mailto:yaaang@gmail.com>`_, and `Zhuoyun Wei <wzyboy@wzyboy.org>`_.