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[unix-history] / usr / src / bin / ln / ln.1

.\" Copyright (c) 1980, 1990 The Regents of the University of California.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" the Institute of Electrical and Electronics Engineers, Inc.
.\"
.\" %sccs.include.redist.man%
.\"
.\"     @(#)ln.1	6.7 (Berkeley) %G%
.\"
.Vx
.Dd 
.Dt LN 1
.Os BSD 4
.Sh NAME
.Nm ln
.Nd make links
.Sh SYNOPSIS
.Nm ln
.Op Fl s
.Ar source_file
.Op target_file
.Nm ln
.Op Fl s
.Ar source_file ...
.Op target_dir
.Sh DESCRIPTION
The
.Nm ln
utility creates a new
directory entry (linked file)
which inherits the same modes as the orginal
file.
It is useful for maintaining multiple copies of a file in
many places at once - without the `copies'; instead,
a link `points' to the original copy.
There are two types of links; hard links and symbolic links.
How a link `points' to a file is one of the differences
between a hard or symbolic link.
.Pp
Option available:
.Tw Ds
.Tp Fl s
Create a symbolic link.
.Tp
.Pp
By default
.Nm ln
makes
.Em hard
links.
A hard link to a file is indistinguishable from the
original directory entry; any changes to a
file are effective independent of the name used
to reference the file.  Hard links may not refer to directories
(unless the proper incantations are supplied) and may not span
file systems.
.Pp
A symbolic link contains the name of the file to
which it is linked.  The referenced file is used when an
.Xr open  2
operation is performed on the link.
A
.Xr stat  2
on a symbolic link will return the linked-to file; an
.Xr lstat  2
must be done to obtain information about the link.
The
.Xr readlink  2
call may be used to read the contents of a symbolic link.
Symbolic links may span file systems and may refer to directories.
.Pp
Given one or two arguments,
.Nm ln
creates a link to an existing file
.Ar source_file  .
If
.Ar target_file
is given, the link has that name;
.Ar target_file
may also be a directory in which to place the link;
otherwise it is placed in the current directory.
If only the directory is specified, the link will be made
to the last component of
.Ar source_file  .
.Pp
Given more than two arguments,
.Nm ln
makes links in
.Ar target_dir
to all the named source files.
The links made will have the same name as the files being linked to.
.Sh SEE ALSO
.Xr rm 1 ,
.Xr cp 1 ,
.Xr mv 1 ,
.Xr link 2 ,
.Xr readlink 2 ,
.Xr stat 2 ,
.Xr symlink 2
.Sh HISTORY
A
.Nm ln
command appeared in Version 6 AT&T Unix.