Tribblix: manual page: ln.1

LN(1) User Commands LN(1)

NAME

ln - make hard or symbolic links to files

SYNOPSIS

/usr/bin/ln [-fins] source_file [target]

/usr/bin/ln [-fins] source_file... target

/usr/xpg4/bin/ln [-fis] source_file [target]

/usr/xpg4/bin/ln [-fis] source_file... target

DESCRIPTION

In the first synopsis form, the ln utility creates a new directory
entry (link) for the file specified by source_file, at the
destination path specified by target. If target is not specified, the
link is made in the current directory. This first synopsis form is
assumed when the final operand does not name an existing directory;
if more than two operands are specified and the final is not an
existing directory, an error will result.

In the second synopsis form, the ln utility creates a new directory
entry for each file specified by a source_file operand, at a
destination path in the existing directory named by target.

The ln utility may be used to create both hard links and symbolic
links. A hard link is a pointer to a file and 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 span file systems and may not refer to directories.

ln by default creates hard links. source_file is linked to target. If
target is a directory, another file named source_file is created in
target and linked to the original source_file.

If target is an existing file and the -f option is not specified, ln
will write a diagnostic message to standard error, do nothing more
with the current source_file, and go on to any remaining
source_files.

A symbolic link is an indirect pointer to a file; its directory entry
contains the name of the file to which it is linked. Symbolic links
may span file systems and may refer to directories.

File permissions for target may be different from those displayed
with an -l listing of the ls(1) command. To display the permissions
of target, use ls -lL. See stat(2) for more information.

/usr/bin/ln
If /usr/bin/ln determines that the mode of target forbids writing, it
prints the mode (see chmod(1)), asks for a response, and reads the
standard input for one line. If the response is affirmative, the link
occurs, if permissible. Otherwise, the command exits.

/usr/xpg4/bin/ln
When creating a hard link, and the source file is itself a symbolic
link, the target will be a hard link to the file referenced by the
symbolic link, not to the symbolic link object itself (source_file).

OPTIONS

The following options are supported for both /usr/bin/ln and
/usr/xpg4/bin/ln:

-f
Links files without questioning the user, even if the mode of
target forbids writing. If both the -f and -i options are
specified, only the last one on the command line is honored.

-i
Interactively prompt the user about how to proceed when target
already exists. An affirmative response means that target
should be removed so that a link can be created. Any other
answer will prevent the overwriting. If both the -f and -i
options are specified, only the last one on the command line is
honored.

-s
Creates a symbolic link.

If the -s option is used with two arguments, target may be an
existing directory or a non-existent file. If target already
exists and is not a directory, an error is returned.
source_file may be any path name and need not exist. If it
exists, it may be a file or directory and may reside on a
different file system from target. If target is an existing
directory, a file is created in directory target whose name is
source_file or the last component of source_file. This file is
a symbolic link that references source_file. If target does not
exist, a file with name target is created and it is a symbolic
link that references source_file.

If the -s option is used with more than two arguments, target
must be an existing directory or an error will be returned. For
each source_file, a link is created in target whose name is the
last component of source_file. Each new source_file is a
symbolic link to the original source_file. The files and target
may reside on different file systems.

/usr/bin/ln
The following option is supported for /usr/bin/ln only:

-n
If target is an existing file, writes a diagnostic message to
stderr and goes on to any remaining source_files. The -f and -i
options override this option. This is the default behavior for
/usr/bin/ln and /usr/xpg4/bin/ln, and is silently ignored.

OPERANDS

The following operands are supported:

source_file
A path name of a file to be linked. This can be either
a regular or special file. If the -s option is
specified, source_file can also be a directory.

target
The path name of the new directory entry to be
created, or of an existing directory in which the new
directory entries are to be created.

USAGE

See largefile(7) for the description of the behavior of ln when
encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).

ENVIRONMENT VARIABLES

See environ(7) for descriptions of the following environment
variables that affect the execution of ln: LANG, LC_ALL, LC_CTYPE,
LC_MESSAGES, and NLSPATH.

EXIT STATUS

The following exit values are returned:

0
All the specified files were linked successfully

>0
An error occurred.

ATTRIBUTES

NOTES

A symbolic link to a directory behaves differently than you might
expect in certain cases. While an ls(1) command on such a link
displays the files in the pointed-to directory, entering ls -l
displays information about the link itself:

example% ln -s dir link
example% ls link
file1 file2 file3 file4
example% ls -l link
lrwxrwxrwx 1 user 7 Jan 11 23:27 link -> dir

When you change to a directory (see cd(1)) through a symbolic link,
using /usr/bin/sh or /usr/bin/csh, you wind up in the pointed-to
location within the file system. This means that the parent of the
new working directory is not the parent of the symbolic link, but
rather, the parent of the pointed-to directory. This will also happen
when using cd with the -P option from /usr/bin/ksh or
/usr/xpg4/bin/sh. For instance, in the following case, the final
working directory is /usr and not /home/user/linktest.

example% pwd
/home/user/linktest
example% ln -s /usr/tmp symlink
example% cd symlink
example% cd ..
example% pwd
/usr

C shell users can avoid any resulting navigation problems by using
the pushd and popd built-in commands instead of cd.

September 14, 2024 LN(1)