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/>.