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 1.8 2008/09/07 07:54:48 swildner Exp $ 38.\" 39.Dd September 27, 2009 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. 89This is most useful with the 90.Fl f 91option, to replace a symlink which may point to a directory. 92.It Fl i 93Cause 94.Nm 95to write a prompt to standard error if the target file exists. 96If the response from the standard input begins with the character 97.Sq Li y 98or 99.Sq Li Y , 100then unlink the target file so that the link may occur. 101Otherwise, do not attempt the link. 102(The 103.Fl i 104option overrides any previous 105.Fl f 106options.) 107.It Fl n 108Same as 109.Fl h , 110for compatibility with other 111.Nm 112implementations. 113.It Fl s 114Create a symbolic link. 115.It Fl v 116Cause 117.Nm 118to be verbose, showing files as they are processed. 119.El 120.Pp 121By default, 122.Nm 123makes 124.Em hard 125links. 126A hard link to a file is indistinguishable from the original directory entry; 127any changes to a file are effectively independent of the name used to reference 128the file. 129Hard links may not normally refer to directories and may not span file systems. 130.Pp 131A symbolic link contains the name of the file to which it is linked. 132The referenced file is used when an 133.Xr open 2 134operation is performed on the link. 135A 136.Xr stat 2 137on a symbolic link will return the linked-to file; an 138.Xr lstat 2 139must be done to obtain information about the link. 140The 141.Xr readlink 2 142call may be used to read the contents of a symbolic link. 143Symbolic links may span file systems and may refer to directories. 144.Pp 145Given one or two arguments, 146.Nm 147creates a link to an existing file 148.Ar source_file . 149If 150.Ar target_file 151is given, the link has that name; 152.Ar target_file 153may also be a directory in which to place the link; 154otherwise it is placed in the current directory. 155If only the directory is specified, the link will be made 156to the last component of 157.Ar source_file . 158.Pp 159Given more than two arguments, 160.Nm 161makes links in 162.Ar target_dir 163to all the named source files. 164The links made will have the same name as the files being linked to. 165.Pp 166When the utility is called as 167.Nm link , 168exactly two arguments must be supplied, 169neither of which may specify a directory. 170No options may be supplied in this simple mode of operation, 171which performs a 172.Xr link 2 173operation using the two passed arguments. 174.Sh VARIANT SYMLINKS 175.Dx 176supports a special kind of dynamic 177symbolic link called a 178.Em variant symlink . 179The 180.Ar source_file 181of a variant symlink may contain one or more variable names. 182Each of these variable names is enclosed in braces and preceded by a 183dollar sign in the style of variable references in 184.Xr sh 1 185and 186.Xr csh 1 . 187.Pp 188Whenever a variant symlink is followed, each variable 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. 193The facility supports per-process, per-user, and system-wide varsyms. 194.Pp 195Varsym variables can be set with the 196.Xr varsym 1 197utility. 198Regular 199.Xr environ 7 200environment variables are not used to resolve variant symlinks. 201.Sh EXAMPLES 202.Bd -literal -offset indent 203sysctl 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 COMPATIBILITY 214The 215.Fl h , 216.Fl i , 217.Fl n 218and 219.Fl v 220options are non-standard and their use in scripts is not recommended. 221They are provided solely for compatibility with other 222.Nm 223implementations. 224.Pp 225Variant symlinks are unique (among BSDs) to 226.Dx . 227.Sh SEE ALSO 228.Xr varsym 1 , 229.Xr link 2 , 230.Xr lstat 2 , 231.Xr readlink 2 , 232.Xr stat 2 , 233.Xr symlink 2 , 234.Xr symlink 7 235.Sh STANDARDS 236The 237.Nm 238utility conforms to 239.St -p1003.2-92 . 240.Pp 241The simplified 242.Nm link 243command conforms to 244.St -susv2 . 245.Sh HISTORY 246An 247.Nm 248command appeared in 249.At v1 . 250