ln(1)ln(1)NAMEln - Make a hard link or a symbolic link to a file
SYNOPSISln [-fs] sourcename [targetname]
ln [-fs] sourcename... targetdirectory
ln [-fns] sourcename targetname
ln [-fns] sourcename... targetdirectory
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Forces the removal of existing target path names before linking.
[Tru64 UNIX] Creates symbolic links. [Tru64 UNIX] If the target
already exists, do not create the link, and issue an error message.
The -f option overrides the -n option. To use the -n option, the
CMD_ENV environment variable must be set to svr4.
Path name of a file to be linked. The path name of the new directory
entry to be created. A path name of an existing directory in which new
entries are to be created.
A link is a directory entry that refers to a file. Usually, sourcename
is an existing file, and targetname does not exist. Thus, targetname
becomes a new name, or pseudonym for sourcename. A file, together with
its size and all its protection information, can have several links to
it. There are two kinds of links: hard links and symbolic links.
[Tru64 UNIX] By default ln makes hard links. A hard link to a file is
indistinguishable from the original directory entry. Changes to either
file affect both files. Hard links must be made to files in the local
file system: they cannot span file systems and cannot refer to directo‐
[Tru64 UNIX] With the -s option, the command makes symbolic links,
including Context Dependent Symbolic Links (CDSLs). A symbolic link
contains the name of the file to which it is linked. The referenced
file is used when an open() operation is performed on the link. A
stat() on a symbolic link returns the linked-to file. An lstat() must
be done to obtain information about the link. The readlink() call can
be used to read the contents of a symbolic link. Symbolic links can
span file systems and can refer to directories.
Given one or two arguments, ln creates a link to an existing sourcename
file. If targetname is omitted, then sourcename is used for the link,
but it must be created in a different directory than that of the
source file. If targetname is given, the link has that name. The tar‐
getname can also be a directory in which to place the link; otherwise,
it is placed in the current directory. If only the directory is speci‐
fied, the link is made to the last component of the sourcename file.
Given more than two arguments, ln makes links to all the specified
files (sourcename) in the specified targetdirectory. The links made
have the same name as the files to which they are being linked.
If targetname exists, the command aborts unless the -f option is used.
SVID and System V Release 4 Conformance
[Tru64 UNIX] When the environment variable CMD_ENV is set to svr4, the
behavior of the base ln command is compatible with its behavior under
System V Release 4. There is also a version of the ln command provided
in the System V habitat that is conformant with the SVID standard. For
more information on the System V habitat, see the Command and Shell
This section documents the behavior of the habitat version, and of the
base version with CMD_ENV set to svr4, insofar as the behavior differs
from that of the base ln command without CMD_ENV set. This section
discusses only hard links.
[Tru64 UNIX] In contrast to the base ln command without CMD_ENV set,
these versions of ln silently overwrite an existing targetname if it is
not a directory and has write permission. The -n option, available
only in the base command when CMD_ENV is set, prevents overwriting such
an existing target. Thus, for such an existing targetname, the base
command ln-n with CMD_ENV set behaves the same as does the base com‐
mand ln with no options and with CMD_ENV not set.
[Tru64 UNIX] If the targetname exists, is not a directory, and does
not have write permission, three possible conditions can exist, with
each condition producing a different behavior: [Tru64 UNIX] If the
standard input is not a terminal, the command attempts to silently
unlink targetname and link the source file to it. [Tru64 UNIX] If the
standard input is a terminal and the command line does not include the
-f option, the command prompts the user for permission to unlink tar‐
getname. The habitat command compares the user response to the system
defined values for YESSTR and NOSTR. If the user response matches the
value for YESSTR, the command attempts to unlink the target file and
link the source file to targetname. If the user response matches
NOSTR, the command aborts. Similarly, with the base command and
CMD_ENV set, the operation aborts unless the user response begins with
a y. [Tru64 UNIX] If the standard input is a terminal and the command
line includes the -f option, the command attempts to silently unlink
targetname and link the source file to it.
[Tru64 UNIX] You cannot link files across file systems without using
the -s option. That is, links across file systems must be symbolic
The following exit values are returned: All the specified files were
linked successfully. An error occurred.
The following example creates a link (also called an alias) to a file:
ln chap1 intro
The previous command links chap1 to the intro file. If intro
does not already exist, the file name is created. If intro does
exist and permissions allow, the file is replaced by a link to
chap1. The following command forces the link even if intro
exists and permissions do not allow it to be overwritten: ln-f
The previous command causes chap1 and intro to refer to the same
file. Any changes made to one file also appear in the other
file. If one name is deleted with the rm command, the file is
not actually deleted because it remains under the other name.
The following command links a file to the same name in an exist‐
ing directory: ln index manual
The previous command links index to the new name manual/index.
The following command links several files to names in another
directory: ln chap2 jim/chap3 /u/manual
The previous command links chap2 to the new name /u/manual/chap2
and links jim/chap3 to /u/manual/chap3. The following command
uses ln with pattern-matching characters: ln manual/* .
The previous command links all files in the directory manual
into the current directory (.), giving them the same names they
have in manual. Note that you must type a space between the *
(asterisk) and the (dot). The following command creates a link
to the final component of a path name: ln-s /a/b/c/d/e
This creates a link, e, in the current directory to the file
/a/b/c/d/e. The following command creates a link to a direc‐
tory. In this example, t1 is a subdirectory under d1: ln-s
This creates a link from /d1/t1 to /d2 as follows: # ls -lF /d2
lrwxrwxrwx 1 root system 11 Dec 13 14:00 /d2@ -> /d1/t1/
The path name for sourcename must be specified if the sourcename
differs from that of the targetdirectory. If the path name is
not specified, a link is created to a file, not to the intended
directory. For example, if the path name was not specified in
this example, ls -s t1 /d2 creates a link to a file named t1,
instead of the directory /d1/t1.
The following environment variables affect the execution of ln: [Tru64
UNIX] When this environment variable is set to svr4, the behavior of
the ln command is compatible with its behavior under System V Release
4. The -n option requires that this environment variable be set to
svr4. Provides a default value for the internationalization variables
that are unset or null. If LANG is unset or null, the corresponding
value from the default locale is used. If any of the internationaliza‐
tion variables contain an invalid setting, the utility behaves as if
none of the variables had been defined. If set to a non-empty string
value, overrides the values of all the other internationalization vari‐
ables. Determines the locale for the interpretation of sequences of
bytes of text data as characters (for example, single-byte as opposed
to multibyte characters in arguments). Determines the locale for the
format and contents of diagnostic messages written to standard error.
Determines the location of message catalogues for the processing of
Commands: cp(1), mv(1), rm(1)
Functions: chmod(2), link(2), open(2), readlink(2), stat(2), sym‐
Command and Shell User's Guide