LN(1)

LN(1) | General Commands Manual | LN(1)

# NAME

`ln` —
link files

# SYNOPSIS

`ln` | [`-L` | `-P` | `-s` [`-F`]] [`-f` | `-iw`] [`-hnv`] source_file [target_file]

`ln` | [`-L` | `-P` | `-s` [`-F`]] [`-f` | `-iw`] [`-hnv`] source_file ... target_dir

# DESCRIPTION

The `ln` utility creates a new directory entry (linked file) for the file name specified by target_file. The target_file will be created with the same file modes as the source_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`
  If the target file already exists and is a directory, then remove it so that the link may occur. The `-F` option should be used with either `-f` or `-i` options. If none is specified, `-f` is implied. The `-F` option is a no-op unless `-s` option is specified.
`-L`
  When creating a hard link to a symbolic link, create a hard link to the target of the symbolic link. This is the default. This option cancels the `-P` option.
`-P`
  When creating a hard link to a symbolic link, create a hard link to the symbolic link itself. This option cancels the `-L` option.
`-f`
  If the target file already exists, then unlink it so that the link may occur. (The `-f` option overrides any previous `-i` and `-w` options.)
`-h`
  If the target_file or target_dir is a symbolic link, do not follow it. This is most useful with the `-f` option, to replace a symlink which may point to a directory.
`-i`
  Cause `ln` to write a prompt to standard error if the target file exists. If the response from the standard input begins with the character ‘`y`’ or ‘`Y`’, then unlink the target file so that the link may occur. Otherwise, do not attempt the link. (The `-i` option overrides any previous `-f` options.)
`-n`
  Same as `-h`, for compatibility with other `ln` implementations.
`-s`
  Create a symbolic link.
`-v`
  Cause `ln` to be verbose, showing files as they are processed.
`-w`
  Warn if the source of a symbolic link does not currently exist.

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. Directories may not be hardlinked, and hard links 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 linked-to 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 and may refer to directories.

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

Create a symbolic link named /home/src and point it to /usr/src:

`# ln -s /usr/src /home/src`

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

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

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.

In the next example, the second call to `ln` removes the original foo and creates a replacement pointing to baz:

    # mkdir bar baz
    # ln -s bar foo
    # ln -shf baz foo

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.

An easy rule to remember is that the argument order for `ln` is the same as for cp(1): The first argument needs to exist, the second one is created.

# COMPATIBILITY

The `-h`, `-i`, `-n`, `-v` and `-w` options are non-standard and their use in scripts is not recommended. They are provided solely for compatibility with other `ln` implementations.

The `-F` option is a FreeBSD extension and should not be used in portable scripts.

# SEE ALSO

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

# STANDARDS

The `ln` utility conforms to IEEE Std 1003.2-1992 (“POSIX.2”).

# HISTORY

An `ln` command appeared in Version 1 AT&T UNIX.

April 20, 2017 | NetBSD 10.1