hardlink man page

hardlink — Consolidate duplicate files via hardlinks

Synopsis

hardlink [options] [directory...]

Description

This manual page documents hardlink, a program which consolidates duplicate files in one or more directories using hardlinks.

hardlink traverses one or more directories searching for duplicate files.  When it finds duplicate files, it uses one of them as the master.  It then removes all other duplicates and places a hardlink for each one pointing to the master file. This allows for conservation of disk space where multiple directories on a single filesystem contain many duplicate files.

Since hard links can only span a single filesystem, hardlink is only useful when all directories specified are on the same filesystem.

Options

-c, --content

Compare only the contents of the files being considered for consolidation. Disregards permission, ownership and other differences.

-f, --force

Force hardlinking across file systems.

-n, --dry-run

Do not perform the consolidation; only print what would be changed.

-v, --verbose

Print summary after hardlinking. The option may be specified more than once. In this case (e.g. -vv) it prints every hardlinked file and bytes saved.

-x, --exclude regex

Exclude files and directories matching pattern from hardlinking.

The optional pattern for excluding files and directories must be a PCRE2 compatible regular expression. Only the basename of the file or directory is checked, not its path. Excluded directories' contents will not be examined.

-h, --help

Display help text and exit.

-V, --version

Display version information and exit.

Author

hardlink was written by Jakub Jelinek <jakub@redhat.com> and later modified by Ruediger Meier <ruediger.meier@ga-group.nl> and Karel Zak <kzak@redhat.com> for util-linux.

Man page written by Brian Long and later updated by Jindrich Novy <jnovy@redhat.com>

Bugs

hardlink assumes that its target directory trees do not change from under it.  If a directory tree does change, this may result in hardlink accessing files and/or directories outside of the intended directory tree. Thus, you must avoid running hardlink on potentially changing directory trees, and especially on directory trees under control of another user.

Historically hardlink silently excluded any names beginning with ".in.", as well as any names beginning with "." followed by exactly 6 other characters. That prior behavior can be achieved by specifying
-x '^(\.in\.|\.[^.]{6}$)'

Availability

The hardlink command is part of the util-linux package and is available from https://www.kernel.org/pub/linux/utils/util-linux/.