README.md

Hash Backup Tool

This program is used to create backups of a given folder tree by referencing each file by its hash. Each additional backup to the same backup dir will only add new files that have a different hash, so space is conserved. All file and folder timestamps (made available in node.js) are preserved (although only atime and mtime can be restored), and so are empty folders.

Usage

Download hash_backup.js and place anywhere. Run node hash_backup.js to see available commands.

Help

Node Hash Backup Tool

Usage: node hash_backup.js [command] [options]

Command `init`:
  Initalizes empty hash backup in backup dir.
  
  Options:
    --to <backupDir> (required): The hash backup dir to initialize.
    --hash <algorithm> (default `sha384`): The hash algorithm to use on the files.
    --hash-slice-length (default `2`): The length of the hash slice used to split files into folders.
    --hash-slices (default `2`): The number of nested subfolders of hash slices each file should be under.
    --compress-algo (default `brotli`): The algorithm to compress files (`none` for no algo).
    --compress-level (default 6): The amount to compress files (valid is 1 through 9).

Command `delete`:
  Removes all files at hash backup dir.
  
  Options:
    --to <backupDir> (required): The hash backup dir to remove contents of.

Command `list`:
  Lists the backups in a given hash backup folder.
  
  Options:
    --to <backupDir> (required): The hash backup folder to use.
    --name <name> (optional): The name of the backup to show information about specifically.

Command `backup`:
  Backs up a folder to the hash backup.
  
  Options:
    --from <basePath> (required): The directory to backup.
    --to <backupDir> (required): The hash backup folder to use.
    --name <name> (required): The name of the backup.
    --ignore-symlinks <value> (default false): If true, symlinks will be ignored (not implemented yet). If false, symlinks will be copied over as regular files (and the modtime of the destination file will be used).
    --in-memory <value> (default true): Read file into memory and store hash and compressed forms into memory. Minimizes hard drive reads/writes. Turn off for files too large to fit in memory (not implemented yet).
    --check-duplicate-hashes (default true): If true, check for whether files are truly equal if their hashes are (false not implemented yet, true will error if hashes match as duplicate hash handling not implemented yet).

Command `restore`:
  Restores a folder from the hash backup.
  
  Options:
    --from <backupDir> (required): The hash backup folder to use.
    --to <basePath> (required): The directory to restore to.
    --name <name> (required): The name of the backup.
    --verify <value> (default true): If true, file checksums will be verified as they are copied out.

Command `remove`:
  Removes a backup from the hash backup.
  
  Options:
    --to <backupDir> (required): The hash backup folder to use.
    --name <name> (required): The name of the backup.
    --auto-purge (default true): If true, automatically purge files no longer referenced by any backup. (false not implemented yet)