ln.1

早期freebsd实现

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.\"	@(#)ln.1	8.2 (Berkeley) 12/30/93
.\"
.Dd December 30, 1993
.Dt LN 1
.Os BSD 4
.Sh NAME
.Nm ln
.Nd make links
.Sh SYNOPSIS
.Nm ln
.Op Fl fs
.Ar source_file
.Op target_file
.Nm ln
.Op Fl fs
.Ar source_file ...
.Op target_dir
.Sh DESCRIPTION
The
.Nm 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
.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 s
Create a symbolic link.
.El
.Pp
By default
.Nm ln
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 ln
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 ln
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.
.Sh SEE ALSO
.Xr link 2 ,
.Xr lstat 2 ,
.Xr readlink 2 ,
.Xr stat 2 ,
.Xr symlink 2 ,
.Xr symlink 7
.Sh HISTORY
A
.Nm ln
command appeared in
.At v6 .