hardlink

HARDLINK(1)                      User Commands                     HARDLINK(1)

NAME
       hardlink - link multiple copies of a file

SYNOPSIS
       hardlink [options] [directory|file]...

DESCRIPTION
       hardlink is a tool which replaces copies of a file with hardlinks,
       therefore saving space.

OPTIONS
       -h, --help
           print quick usage details to the screen.

       -v, --verbose
           More verbose output. If specified once, every hardlinked file is
           displayed, if specified twice, it also shows every comparison.

       -q, --quiet
           Quiet mode, don't print anything.

       -n, --dry-run
           Do not act, just print what would happen.

       -f, --respect-name
           Only try to link files with the same (base)name. It's strongly
           recommended to use long options rather than -f which is interpreted
           in a different way by other hardlink implementations.

       -p, --ignore-mode
           Link and compare files even if their mode is different. Results may
           be slightly unpredictable.

       -o, --ignore-owner
           Link and compare files even if their owner information (user and
           group) differs. Results may be unpredictable.

       -t, --ignore-time
           Link and compare files even if their time of modification is
           different. This is usually a good choice.

       -X, --respect-xattrs
           Only try to link files with the same extended attributes.

       -m, --maximize
           Among equal files, keep the file with the highest link count.

       -M, --minimize
           Among equal files, keep the file with the lowest link count.

       -O, --keep-oldest
           Among equal files, keep the oldest file (least recent modification
           time). By default, the newest file is kept. If --maximize or
           --minimize is specified, the link count has a higher precedence
           than the time of modification.

       -x, --exclude regex
           A regular expression which excludes files from being compared and
           linked.

       -i, --include regex
           A regular expression to include files. If the option --exclude has
           been given, this option re-includes files which would otherwise be
           excluded. If the option is used without --exclude, only files
           matched by the pattern are included.

       -s, --minimum-size size
           The minimum size to consider. By default this is 1, so empty files
           will not be linked. The size argument may be followed by the
           multiplicative suffixes KiB (=1024), MiB (=1024*1024), and so on
           for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is optional, e.g.,
           "K" has the same meaning as "KiB").

       -S, --buffer-size size
           The size of read buffer used when comparing file contents (default:
           8KiB). This costs some additional memory but potentially reduces
           the amount of seek operations and therefore improve performance,
           especially with mechanic disk drives. Optional factor suffixes are
           supported, like with the -s option. This is mostly efficient with
           other filters (i.e. with -f or -X) and can be less efficient with
           -top options.

ARGUMENTS
       hardlink takes one or more directories which will be searched for files
       to be linked.

BUGS
       The original hardlink implementation uses the option -f to force
       hardlinks creation between filesystem. This very rarely usable feature
       is no more supported by the current hardlink.

       hardlink assumes that the trees it operates on do not change during
       operation. If a tree does change, the result is undefined and
       potentially dangerous. For example, if a regular file is replaced by a
       device, hardlink may start reading from the device. If a component of a
       path is replaced by a symbolic link or file permissions change,
       security may be compromised. Do not run hardlink on a changing tree or
       on a tree controlled by another user.

AUTHOR
       There are multiple hardlink implementations. The very first
       implementation is from Jakub Jelinek for Fedora distribution, this
       implementation has been used in util-linux between versions v2.34 to
       v2.36. The current implementations is based on Debian version from
       Julian Andres Klode.

REPORTING BUGS
       For bug reports, use the issue tracker at
       https://github.com/karelzak/util-linux/issues.

AVAILABILITY
       The hardlink command is part of the util-linux package which can be
       downloaded from Linux Kernel Archive
       <https://www.kernel.org/pub/linux/utils/util-linux/>.

util-linux 2.37.2                 2024-04-09                       HARDLINK(1)