ln(1BSD) (BSD System Compatibility) ln(1BSD)
NAME
ln - (BSD) make hard or symbolic links to files
SYNOPSIS
/usr/ucb/ln [-fs] file [linkname]
/usr/ucb/ln [-fs] pathname . . . directory
DESCRIPTION
/usr/ucb/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, and so on.
file 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 file 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 /usr/ucb/ls on such a
link displays the files in the pointed-to directory, an
`/usr/ucb/ls -l' displays information about the link itself:
example% /usr/ucb/ln -s dir link
example% /usr/ucb/ls link
file1 file2 file3 file4
Copyright 1994 Novell, Inc. Page 1
ln(1BSD) (BSD System Compatibility) ln(1BSD)
example% /usr/ucb/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 /var and not /home/user/linktest.
example% pwd
/home/var/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.
-s Create a symbolic link or links.
EXAMPLE
The commands below illustrate the effects of the different
forms of the /usr/ucb/ln command:
example% /usr/ucb/ln file link
example% /usr/ucb/ls -F file link
file link
example% /usr/ucb/ln -s file symlink
example% /usr/ucb/ls -F file symlink
file symlink@
example% /usr/ucb/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% /usr/ucb/ls -F devoid
devoid@
example% cat devoid
ux:cat: ERROR: Cannot open devoid: No such file or directory
example% /usr/ucb/ln -s /proto/bin/* /tmp/bin
example% /usr/ucb/ls -F /proto/bin /tmp/bin
Copyright 1994 Novell, Inc. Page 2
ln(1BSD) (BSD System Compatibility) ln(1BSD)
/proto/bin:
x* y* z*
/tmp/bin:
x@ y@ z@
REFERENCES
cp(1), link(2), ls(1), ls(1BSD), mv(1), readlink(2), rm(1)
stat(2), symlink(2)
NOTICES
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
ux:cat:ERROR:Cannot open /tmp/file:
Too many symbolic links in pathname traversal.
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
example% /usr/ucb/ls -l /tmp/file
lrwxrwxrwx 1 user
4 Jan 12 00:16 /tmp/file -> /home/user/subdir/file
Copyright 1994 Novell, Inc. Page 3