NAME
ln - make hard or symbolic links to files
SYNOPSIS
ln [ -fs ] filename [ linkname ]
ln [ -fs ] pathname... directory
SYSTEM V SYNOPSIS
/usr/5bin/ln [ -fFs ] filename [ linkname ]
ln [ -fFs ] pathname... directory
AVAILABILITY
The System V version of this command is available with the
System V software installation option. Refer to Installing
SunOS 4.1 for information on how to install optional
software.
DESCRIPTION
ln 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;
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(1V) on such a
link displays the files in the pointed-to directory, an `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 cd(1) 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% ln -s /usr/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.
SYSTEM V DESCRIPTION
The System V version of ln behaves as described above except
for the following. If the linkname is an existing file and
its mode does not forbid writing, then its contents are des-
troyed. If however its mode does not allow writing, the
mode is printed, and the user asked for a response.
OPTIONS
-f Force a hard link to a directory - this option is only
available to the super-user.
-s Create a symbolic link or links.
SYSTEM V OPTIONS
-f Force files to be linked without displaying permis-
sions, asking questions or reporting errors.
-F Force a hard link to a directory - this option is only
available to the super-user.
-s Create a symbolic link or links.
EXAMPLE
The commands below illustrate the effects of the different
forms of the ln command:
example% ln file link
example% ls -F file link
file link
example% 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% ln -s nonesuch devoid
example% ls -F devoid
devoid@
example% cat devoid
devoid: No such file or directory
example% 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(1V), mv(1), rm(1), link(2V), readlink(2),
stat(2V), symlink(2)
BUGS
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% 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 direc-
tory:
example% rm /tmp/file
example% ln -s $PWD/file /tmp
lrwxrwxrwx 1 user 4 Jan 12 00:16 /tmp/file -> /home/user/subdir/file