shatag(1)							      Shatag								 shatag(1)

NAME

       shatag - tag files with their SHA-256 checksums

SYNOPSIS

       shatag [-fhlLqrtuv0] [-d DATABASE] [-n NAME] [-R NAME]...  [FILES]...

DESCRIPTION

       shatag  is a tool for computing and caching SHA-256 file checksums, and efficiently search for identical file across systems. Checksums are
       stored using the POSIX Extended Attributes filesystem facility, and are preserved when files  are  moved  or  renamed.	Checksums  can	be
       fetched from a remote host and stored in an sqlite database for fast lookups.

OPTIONS

       When  invoked  with  no	options, shatag just displays the cached, valid checksums. If no files are specified, it applies to all non-hidden
       files in the current directory. The output format is identical to the one of the sha256sum command.

       -0, --null
	      Instead of outputting one record per line (like sha256sum does,) separate records with null characters.

       -d DATABASE, --database DATABASE
	      Set the path of the SQLite database to query when using -l , -L or -p (The default path is  $HOME/.shatagdb,  overridable  from  the
	      config file)

	      Instead of a file name, a PostgreSQL database can be specified with a prefix of "pg:" followed by a psycopg2 DSN string, like:

	      "pg:dbname=shatag user=myuser password=mypassword host=192.168.1.3"

       -f, --force
	      When running with -t or -u , recompute the checksum even if the file modification time has not changed. If the old checksum differs,
	      report the file as corrupted.

       -h, --help
	      Displays the help message

       -l, --lookup
	      Instead of displaying the checksums, look them up against the local database and indicate if the file exists. A yellow - mark  indi-
	      cates  that  the file does not exist somewhere else, a green = that the file exists at one or several remote locations, a red + that
	      the file has a duplicate on the local system, and a magenta * that the file is empty.

       -L, --lookup-verbose
	      Instead of displaying the checksums, look them up against the local database.  Print all the known remote  locations  for  identical
	      files.

       -n NAME, --name NAME
	      Name  of	local storage (defaults to canonical local host name). This needs to be correct if the local database contains entries for
	      this own host.

       -p, --put
	      Record found tags in the database, for duplicate detection.

       -q, --quiet
	      Do not display the valid checksums when they are found.

       -r, --recursive
	      Recurse trough subdirectories

       -R NAME, --remote NAME
	      When using -l or -L , This is used to restrict the set of remote names to consider. If present, other storages will be ignored.

       -t, --tag
	      Compute new checksums for files that don't have one, or when it is outdated.

       -u, --update
	      Recompute the outdated checksums only. Be aware that this can behave counter-intuitively; outdated checksums will  only  exists  for
	      files  that  have been appended to or partially modified.  Many programs dealing with small files (some well-known text editors, no-
	      tably) will overwrite the whole file when saving, and the new file will be lacking a checksum entirely. For these cases, use -t  in-
	      stead.

       -v, --verbose
	      Report encoutered files that have an outated or missing checksum.

EXAMPLES

       Retag a whole directory and record everything to the database:
	      shatag -pqrt .

       Check files in the current directory for remote duplicates:
	      shatag -l

       Show alternate locations for duplicates of a single file:
	      shatag -L somefile

FILES

       ~/.shatagrc
	      YAML  configuration  file. Currently has only two possible configuration keys: "database", which sets the database path (by default,
	      ~/.shatagdb) and "name" for the volume name in the database (default to canonical host name.)

	      Examples:

	      database: /var/lib/shatag.db   # sqlite3 backend database: "pg:  dbname=shatag  host=localhost  user=shatag  password=xxxsecretpass-
	      wordxxx"	 #  postgres backend database: http://service.com/shatag   # http backend database: insecure-https://service.com/shatag  #
	      http backend, skip ssl certificate verification

BUGS

       Support for non-ASCII filenames across systems of different and/or inconsistent encodings have not been fully tested.

       Not all option combinations are sensible.

REPORTING BUGS

       Report shatag bugs to the bugtracker at http://bitbucket.org/maugier/shatag,

SEE ALSO

       shatag-add(1), shatag-mkdb(1)

Shatag 0.1							    26.08.2010								 shatag(1)