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/>.