LN(1B) BSD Compatibility Package Commands LN(1B)

NAME

ln - make hard or symbolic links to files

SYNOPSIS

/usr/ucb/ln [-fs] filename [linkname]


/usr/ucb/ln [-fs] pathname... directory

DESCRIPTION

The /usr/ucb/ln utility creates an additional directory entry, called
a link, to a file or directory. Any number of links can be assigned
to a file. The number of links does not affect other file attributes
such as size, protections, data, etc.


filename is the name of the original file or directory. linkname is
the new name to associate with the file or filename. If linkname is
omitted, the last component of filename is used as the name of the
link.


If the last argument is the name of a directory, symbolic links are
made in that directory for each pathname argument; /usr/ucb/ln uses
the last component of each pathname as the name of each link in the
named directory.


A hard link (the default) is a standard directory entry just like the
one made when the file was created. Hard links can only be made to
existing files. Hard links cannot be made across file systems (disk
partitions, mounted file systems). To remove a file, all hard links
to it must be removed, including the name by which it was first
created; removing the last hard link releases the inode associated
with the file.


A symbolic link, made with the -s option, is a special directory
entry that points to another named file. Symbolic links can span file
systems and point to directories. In fact, you can create a symbolic
link that points to a file that is currently absent from the file
system; removing the file that it points to does not affect or alter
the symbolic link itself.


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

example% /usr/ucb/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 use cd(1) to change to a directory through a symbolic link,
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. For instance, in the following case the final working
directory is /usr and not /home/user/linktest.

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


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

OPTIONS

-f
Force a hard link to a directory. This option is only available
to the super-user, and should be used with extreme caution.


-s
Create a symbolic link or links.

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).

EXAMPLES

Example 1: The /usr/ucb/ln command

The commands below illustrate the effects of the different forms of
the /usr/ucb/ln command:


example% /usr/ucb/ln file link
example% ls -F file link
file link
example% /usr/ucb/ln -s file symlink
example% ls -F file symlink
file symlink@
example% ls -li file link symlink
10606 -rw-r--r-- 2 user 0 Jan 12 00:06 file
10606 -rw-r--r-- 2 user 0 Jan 12 00:06 link
10607 lrwxrwxrwx 1 user 4 Jan 12 00:06 symlink -> file
example% /usr/ucb/ln -s nonesuch devoid
example% ls -F devoid
devoid@
example% cat devoid
devoid: No such file or directory
example% /usr/ucb/ln -s /proto/bin/* /tmp/bin
example% ls -F /proto/bin /tmp/bin
/proto/bin:
x* y* z*

/tmp/bin:
x@ y@ z@

SEE ALSO

cp(1), ls(1), mv(1), rm(1), link(2), readlink(2), stat(2),
symlink(2), attributes(7), largefile(7)

NOTES

When the last argument is a directory, simple basenames should not be
used for pathname arguments. If a basename is used, the resulting
symbolic link points to itself:

example% /usr/ucb/ln -s file /tmp
example% ls -l /tmp/file
lrwxrwxrwx 1 user 4 Jan 12 00:16 /tmp/file -> file
example% cat /tmp/file
/tmp/file: Too many levels of symbolic links


To avoid this problem, use full pathnames, or prepend a reference to
the PWD variable to files in the working directory:

example% rm /tmp/file
example% /usr/ucb/ln -s $PWD/file /tmp
lrwxrwxrwx 1 user 4 Jan 12 00:16 /tmp/file ->
/home/user/subdir/file


March 11, 1994 LN(1B)