1.\" Copyright (c) 1980, 1990, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the Institute of Electrical and Electronics Engineers, Inc. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" @(#)ln.1 8.2 (Berkeley) 12/30/93 36.\" $FreeBSD: src/bin/ln/ln.1,v 1.11.2.8 2003/02/04 07:31:59 keramida Exp $ 37.\" $DragonFly: src/bin/ln/ln.1,v 1.4 2004/01/27 18:36:52 dillon Exp $ 38.\" 39.Dd December 30, 1993 40.Dt LN 1 41.Os 42.Sh NAME 43.Nm ln , 44.Nm link 45.Nd make links 46.Sh SYNOPSIS 47.Nm 48.Op Fl fhinsv 49.Ar source_file 50.Op Ar target_file 51.Nm 52.Op Fl fhinsv 53.Ar source_file ... 54.Ar target_dir 55.Nm link 56.Ar source_file Ar target_file 57.Sh DESCRIPTION 58The 59.Nm 60utility creates a new directory entry (linked file) which has the 61same modes as the original file. 62It is useful for maintaining multiple copies of a file in many places 63at once without using up storage for the 64.Dq copies ; 65instead, a link 66.Dq points 67to the original copy. 68There are two types of links; hard links and symbolic links. 69How a link 70.Dq points 71to a file is one of the differences between a hard and symbolic link. 72.Pp 73The options are as follows: 74.Bl -tag -width flag 75.It Fl f 76If the target file already exists, 77then unlink it so that the link may occur. 78(The 79.Fl f 80option overrides any previous 81.Fl i 82options.) 83.It Fl h 84If the 85.Ar target_file 86or 87.Ar target_dir 88is a symbolic link, do not follow it. This is most useful with the 89.Fl f 90option, to replace a symlink which may point to a directory. 91.It Fl i 92Cause 93.Nm 94to write a prompt to standard error if the target file exists. 95If the response from the standard input begins with the character 96.Sq Li y 97or 98.Sq Li Y , 99then unlink the target file so that the link may occur. 100Otherwise, do not attempt the link. 101(The 102.Fl i 103option overrides any previous 104.Fl f 105options.) 106.It Fl n 107Same as 108.Fl h , 109for compatibility with other 110.Nm 111implementations. 112.It Fl s 113Create a symbolic link. 114.It Fl v 115Cause 116.Nm 117to be verbose, showing files as they are processed. 118.El 119.Pp 120By default, 121.Nm 122makes 123.Em hard 124links. 125A hard link to a file is indistinguishable from the original directory entry; 126any changes to a file are effectively independent of the name used to reference 127the file. 128Hard links may not normally refer to directories and may not span file systems. 129.Pp 130A symbolic link contains the name of the file to 131which it is linked. The referenced file is used when an 132.Xr open 2 133operation is performed on the link. 134A 135.Xr stat 2 136on a symbolic link will return the linked-to file; an 137.Xr lstat 2 138must be done to obtain information about the link. 139The 140.Xr readlink 2 141call may be used to read the contents of a symbolic link. 142Symbolic links may span file systems and may refer to directories. 143.Pp 144Given one or two arguments, 145.Nm 146creates a link to an existing file 147.Ar source_file . 148If 149.Ar target_file 150is given, the link has that name; 151.Ar target_file 152may also be a directory in which to place the link; 153otherwise it is placed in the current directory. 154If only the directory is specified, the link will be made 155to the last component of 156.Ar source_file . 157.Pp 158Given more than two arguments, 159.Nm 160makes links in 161.Ar target_dir 162to all the named source files. 163The links made will have the same name as the files being linked to. 164.Pp 165When the utility is called as 166.Nm link , 167exactly two arguments must be supplied, 168neither of which may specify a directory. 169No options may be supplied in this simple mode of operation, 170which performs a 171.Xr link 2 172operation using the two passed arguments. 173.Sh VARIANT SYMLINKS 174DragonFly supports a special kind of dynamic 175symbolic link called a 176.Em variant symlink . 177The 178.Ar source_file 179of a variant symlink may contain one or more 180variable names. Each of these variable 181names is enclosed in braces and preceded by a 182dollar sign in the style of variable references in 183.Xr sh 1 184and 185.Xr csh 1 . 186.Pp 187Whenever a variant symlink is followed, each 188variable found in 189.Ar source_file 190is replaced by its associated value. 191In this manner, a variant symlink may resolve to different 192paths based on context. The facility 193supports per-process, per-user, and system-wide varsyms. 194.Pp 195Varsym variables can be set with the 196.Xr varsym 1 197utility. Regular 198.Xr environ 7 199environment variables are 200not used to resolve variant symlinks. 201.Ss EXAMPLE 202.Bd -literal -offset indent 203sysctl -w vfs.varsym_enable=1 204 205ln -s 'a${fubar}b' test 206 207echo 'Hello' > axxb 208echo 'Goodbye' > ayyb 209 210varsym fubar=xx; cat test 211varsym fubar=yy; cat test 212.Ed 213.Sh SEE ALSO 214.Xr link 2 , 215.Xr lstat 2 , 216.Xr readlink 2 , 217.Xr stat 2 , 218.Xr symlink 2 , 219.Xr symlink 7 , 220.Xr varsym 1 221.Sh COMPATIBILITY 222The 223.Fl h , 224.Fl i , 225.Fl n 226and 227.Fl v 228options are non-standard and their use in scripts is not recommended. 229They are provided solely for compatibility with other 230.Nm 231implementations. 232.Pp 233Variant symlinks are unique (among BSDs) to DragonFly. 234.Sh STANDARDS 235The 236.Nm 237utility conforms to 238.St -p1003.2-92 . 239.Pp 240The simplified 241.Nm link 242command conforms to 243.St -susv2 . 244.Sh HISTORY 245An 246.Nm 247command appeared in 248.At v1 . 249