[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.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"	@(#)ln.1	6.8 (Berkeley) 7/27/91
.\"
.Dd July 27, 1991
.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:
.Bl -tag -width flag
.It Fl s
Create a symbolic link.
.El
.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
.At v6 .
Commit	Line	Data
7b089094 WJ	1	.\" Copyright (c) 1980, 1990 The Regents of the University of California.
	2	.\" 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 6.8 (Berkeley) 7/27/91
	36	.\"
	37	.Dd July 27, 1991
	38	.Dt LN 1
	39	.Os BSD 4
	40	.Sh NAME
	41	.Nm ln
	42	.Nd make links
	43	.Sh SYNOPSIS
	44	.Nm ln
	45	.Op Fl s
	46	.Ar source_file
	47	.Op target_file
	48	.Nm ln
	49	.Op Fl s
	50	.Ar source_file ...
	51	.Op target_dir
	52	.Sh DESCRIPTION
	53	The
	54	.Nm ln
	55	utility creates a new
	56	directory entry (linked file)
	57	which inherits the same modes as the orginal
	58	file.
	59	It is useful for maintaining multiple copies of a file in
	60	many places at once - without the `copies'; instead,
	61	a link `points' to the original copy.
	62	There are two types of links; hard links and symbolic links.
	63	How a link `points' to a file is one of the differences
	64	between a hard or symbolic link.
65	.Pp
66	Option available:
67	.Bl -tag -width flag
68	.It Fl s
69	Create a symbolic link.
70	.El
71	.Pp
72	By default
73	.Nm ln
74	makes
75	.Em hard
76	links.
77	A hard link to a file is indistinguishable from the
78	original directory entry; any changes to a
79	file are effective independent of the name used
80	to reference the file. Hard links may not refer to directories
81	(unless the proper incantations are supplied) and may not span
82	file systems.
83	.Pp
84	A symbolic link contains the name of the file to
85	which it is linked. The referenced file is used when an
86	.Xr open 2
87	operation is performed on the link.
88	A
89	.Xr stat 2
90	on a symbolic link will return the linked-to file; an
91	.Xr lstat 2
92	must be done to obtain information about the link.
93	The
94	.Xr readlink 2
95	call may be used to read the contents of a symbolic link.
96	Symbolic links may span file systems and may refer to directories.
97	.Pp
98	Given one or two arguments,
99	.Nm ln
100	creates a link to an existing file
101	.Ar source_file .
102	If
103	.Ar target_file
104	is given, the link has that name;
105	.Ar target_file
106	may also be a directory in which to place the link;
107	otherwise it is placed in the current directory.
108	If only the directory is specified, the link will be made
109	to the last component of
110	.Ar source_file .
111	.Pp
112	Given more than two arguments,
113	.Nm ln
114	makes links in
115	.Ar target_dir
116	to all the named source files.
117	The links made will have the same name as the files being linked to.
118	.Sh SEE ALSO
119	.Xr rm 1 ,
120	.Xr cp 1 ,
121	.Xr mv 1 ,
122	.Xr link 2 ,
123	.Xr readlink 2 ,
124	.Xr stat 2 ,
125	.Xr symlink 2
126	.Sh HISTORY
127	A
128	.Nm ln
129	command appeared in
130	.At v6 .