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.\" from
.\"	NetBSD: ln.1,v 1.22 2007/10/29 11:22:59 jnemeth Exp
.\"
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.\"	@(#)ln.1	8.2 (Berkeley) 12/30/93
.\"
.Dd November 15, 2009
.Dt FSU_LN 1
.Os
.Sh NAME
.Nm fsu_ln
.Nd make links from a file system image through rump
.Sh SYNOPSIS
.Nm
.Op Fl o Ar opt_args
.Op Fl s Ar fs_spec_args
.Op Fl t Ar fstype
.Op Fl f
.Ar fsdevice
.Op Fl fhinsv
.Ar fstype fsdevice source_file
.Op Ar target_file
.Nm
.Op Fl o Ar opt_args
.Op Fl s Ar fs_spec_args
.Op Fl t Ar fstype
.Op Fl f
.Ar fsdevice
.Op Fl fhinsv
.Ar fstype fsdevice source_file ... target_dir
.Sh DESCRIPTION
The
.Nm
utility creates a new directory entry (linked file) which has the
same modes as the original file on the
.Ar fstype
file system image contained in
.Ar fsdevice .
It is useful for maintaining multiple copies of a file in many places
at once without using up storage for the
.Dq copies ;
instead, a link
.Dq points
to the original copy.
There are two types of links; hard links and symbolic links.
How a link
.Dq points
to a file is one of the differences between a hard or symbolic link.
.Pp
The options are as follows:
.Bl -tag -width flag
.It Fl f
Unlink any already existing file, permitting the link to occur.
.It Fl h
If the
.Ar target_file
or
.Ar target_dir
is a symbolic link, do not follow it.
This is most useful with the
.Fl f
option, to replace a symlink which may point to a directory.
.It Fl i
Cause
.Nm
to write a prompt to standard error if the target file exists.
If the response from the standard input begins with the character
.Sq Li y
or
.Sq Li Y ,
then unlink the target file so that the link may occur.
Otherwise, do not attempt the link.
(The
.Fl i
option overrides any previous
.Fl f
options.)
.It Fl n
Same as
.Fl h ,
for compatibility with other
.Nm
implementations.
.It Fl s
Create a symbolic link.
.It Fl v
Cause
.Nm
to be verbose, showing files as they are processed.
.El
.Pp
By default
.Nm
makes
.Em hard
links.
A hard link to a file 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 normally refer to directories and may not span file systems.
.Pp
A symbolic link contains the name of the file to
which it is linked.
The referenced file is used when an
.Xr open  2
operation is performed on the link.
A
.Xr stat  2
on a symbolic link will return the linked-to file; an
.Xr lstat  2
must be done to obtain information about the link.
The
.Xr readlink  2
call may be used to read the contents of a symbolic link.
Symbolic links may span file systems and may refer to directories.
.Pp
Given one or two arguments,
.Nm
creates a link to an existing file
.Ar source_file  .
If
.Ar target_file
is given, the link has that name;
.Ar 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
.Ar source_file  .
.Pp
Given more than two arguments,
.Nm
makes links in
.Ar target_dir
to all the named source files.
The links made will have the same name as the files being linked to.