Ubuntu Manpage: shatag - tag files with their SHA-256 checksums

NAME

       shatag - tag files with their SHA-256 checksums

SYNOPSIS

       shatag [-fhlLqrstuv0] [-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 speci‐
fied, 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 char‐
acters.

-c, --canonical
Show canonical (full path) file names.

-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 , force recompute the checksum and overwrite the old one, even if the
timestamp indicates a good checksum.

-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 indicates 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 lo‐
cal 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.

-s, --scrub
Recompute the checksum even if the timestamp indicates it would not be needed, and report incon‐
sistencies. Useful to detect silent corruption.

-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 pro‐
grams dealing with small files (some well-known text editors, notably) will overwrite the whole
file when saving, and the new file will be lacking a checksum entirely. For these cases, use -t
instead.

-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=xxxsecretpasswordxxx"  # 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,