NAME    [Toc]    [Back]

     ln - make hard and symbolic links to files

SYNOPSIS    [Toc]    [Back]

     ln [-fhns] source_file [target_file]
     ln [-fhns] source_file ...  [target_dir]

DESCRIPTION    [Toc]    [Back]

     The ln utility creates a new directory entry  (linked  file)
which has the
     same modes as the original file.  It is useful for maintaining multiple
     copies of a file in many places at  once  without  using  up
storage for the
     copies;  instead,  a  link  ``points'' to the original copy.
There are two
     types of links; hard links and symbolic links.  How  a  link
points to a
     file  is  one of the differences between a hard and symbolic
link.

     The options are as follows:

     -f      Unlink any already  existing  file,  permitting  the
link to occur.

     -h       If  the  target is a symlink to a directory, do not
descend into
             it.

     -n      An alias for -h for compatibility with other operating systems.

     -s      Create a symbolic link.

     By  default, ln makes ``hard'' links.  A hard link to a file
is indistinguishable
 from the original directory entry; any changes  to
a file are
     effectively  independent  of  the name used to reference the
file.  Hard
     links may not normally refer to directories and may not span
file systems.


     A symbolic link contains the name of the file to which it is
linked.  The
     referenced file is used when an open(2)  operation  is  performed on the
     link.   A stat(2) on a symbolic link will return the linkedto file; an
     lstat(2) must be done to obtain information about the  link.
The
     readlink(2)  call may be used to read the contents of a symbolic link.
     Symbolic links may span file systems, refer to  directories,
and refer to
     non-existent files.

     Given one or two arguments, ln creates a link to an existing
file
     source_file.  If target_file is given,  the  link  has  that
name;
     target_file  may  also  be a directory in which to place the
link.  Otherwise,
 it is placed in the current directory.   If  only  the
directory is
     specified,  the  link  will be made to the last component of
source_file.

     Given more than two arguments, ln makes links in  target_dir
to all the
     named  source files.  The links made will have the same name
as the files
     being linked to.

EXAMPLES    [Toc]    [Back]

     # ln -s /var/www /home/www

     Creates a symbolic link named /home/www  and  points  it  to
/var/www.

     # ln /usr/local/bin/fooprog-1.0 /usr/local/bin/fooprog

     Hard      link      /usr/local/bin/fooprog      to      file
/usr/local/bin/fooprog-1.0.

     As an exercise, try the following commands:

           $ ls -i /bin/[
           11553 /bin/[
           $ ls -i /bin/test
           11553 /bin/test

     Note that both files have the same inode; that is, /bin/[ is
essentially
     an  alias for the test(1) command.  This hard link exists so
test(1) may
     be invoked from shell scripts, for example, using the if [ ]
construct.

     $ mkdir bar baz; ln -s bar foo; ln -shf baz foo

     The second call to ln removes the original foo and creates a
replacement
     pointing to baz.  Without the -h option, this would  instead
leave foo
     pointing  to  bar  and  inside  foo create a new symlink baz
pointing to itself.
  This results from directory-walking.

SEE ALSO    [Toc]    [Back]

     link(2), lstat(2), readlink(2),  stat(2),  symlink(2),  symlink(7)

HISTORY    [Toc]    [Back]

     An ln utility appeared in Version 3 AT&T UNIX.

CAVEATS    [Toc]    [Back]

     Since  the source_file must have its link count incremented,
a hard link
     cannot be created to a file which is  flagged  immutable  or
append-only
     (see chflags(1)).

OpenBSD      3.6                        December     30,     1993