misc-utils/hardlink.1

   1 .\" SPDX-License-Identifier: MIT
   2 .\"
   3 .\" Copyright (C) 2008 - 2012 Julian Andres Klode. See hardlink.c for license.
   4 .\" Copyright (C) 2021 Karel Zak <kzak@redhat.com>
   5 .\"
   6 .TH HARDLINK 1 "February 2021" "util-linux" "User Commands"
   7 .SH NAME
   8 hardlink \- link multiple copies of a file
   9 .SH SYNOPSIS
  10 .B hardlink
  11 [ options ]
  12 .RI [ directory | file ]...
  13 .SH DESCRIPTION
  14 .B hardlink
  15 is a tool which replaces copies of a file with hardlinks, therefore saving
  16 space.
  17 .SH OPTIONS
  18 .TP
  19 .BR \-h ,\ \-\-help
  20 print quick usage details to the screen.
  21 .TP
  22 .BR \-v ,\ \-\-verbose
  23 More verbose output. If specified once, every hardlinked file is displayed,
  24 if specified twice, it also shows every comparison.
  25 .TP
  26 .B \-n ,\ \-\-dry\-run
  27 Do not act, just print what would happen
  28 .TP
  29 .BR \-f ,\ \-\-respect\-name
  30 Only try to link files with the same (basename).  It's strongly recommended to
  31 use long options rather than \fI\-f\fR which is interpreted in a different way
  32 by others hardlink implementations.
  33 .TP
  34 .BR \-p ,\ \-\-ignore\-mode
  35 Link/compare files even if their mode is different. This may be a bit unpredictable.
  36 .TP
  37 .BR \-o ,\ \-\-ignore\-owner
  38 Link/compare files even if their owner (user and group) is different. It is not
  39 predictable
  40 .TP
  41 .BR \-t ,\ \-\-ignore\-time
  42 Link/compare files even if their time of modification is different. You almost
  43 always want this.
  44 .TP
  45 .BR \-X , \-\-respect\-xattrs
  46 Only try to link files with the same extended attributes.
  47 .TP
  48 .BR \-m ,\ \-\-maximize
  49 Among equal files, keep the file with the highest link count.
  50 .TP
  51 .BR \-M ,\ \-\-minimize
  52 Among equal files, keep the file with the lowest link count.
  53 .TP
  54 .BR \-O ,\ \-\-keep\-oldest
  55 Among equal files, keep the oldest file (least recent modification time). By
  56 default, the newest file is kept. If \-\-maximize or \-\-minimize is specified,
  57 the link count has a higher precedence than the time of modification.
  58 .TP
  59 .BR \-x ,\ \-\-exclude\ \fIregex\fP
  60 A regular expression which excludes files from being compared and linked.
  61 .TP
  62 .BR \-i ,\ \-\-include\ \fIregex\fP
  63 A regular expression to include files. If the option \-\-exclude has been given,
  64 this option re-includes files which would otherwise be excluded. If the option
  65 is used without \-\-exclude, only files matched by the pattern are included.
  66 .TP
  67 .BR \-s ,\ \-\-minimum\-size\ \fIsize\fP
  68 The minimum size to consider. By default this is 1, so empty files will not
  69 be linked. The \fIsize\fR argument may be followed by the multiplicative
  70 suffixes KiB (=1024), MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB, ZiB
  71 and YiB (the "iB" is optional, e.g., "K" has the same meaning as "KiB").
  72 .SH ARGUMENTS
  73 .B hardlink
  74 takes one or more directories which will be searched for files to be linked.
  75
  76 .SH BUGS
  77 The original hardlink implementation uses the option \fI\-f\fR to force
  78 hardlinks creation between filesystem.  This very rarely usable feature
  79 is no more supported by the current hardlink.
  80 .PP
  81 .B hardlink
  82 assumes that the trees it operates on do not change during
  83 operation. If a tree does change, the result is undefined and potentially
  84 dangerous. For example, if a regular file is replaced by a device, hardlink
  85 may start reading from the device. If a component of a path is replaced by
  86 a symbolic link or file permissions change, security may be compromised. Do
  87 not run hardlink on a changing tree or on a tree controlled by another user.
  88
  89 .SH AUTHOR
  90 There are multiple hardlink implementations.  The very first implementation is
  91 from Jakub Jelinek for Fedora distribution, this implementation has been used
  92 in util-linux between versions v2.34 to v2.36.  The current implementations is
  93 based on Debian version from Julian Andres Klod.
  94
  95 .SH AVAILABILITY
  96 The example command is part of the util-linux package and is available from
  97 .UR https://\:www.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
  98 Linux Kernel Archive
  99 .UE .
 100