| LN(1) | General Commands Manual | LN(1) |
ln —
ln |
[-L | -P |
-s [-F]]
[-f | -iw]
[-hnv] source_file
[target_file] |
ln |
[-L | -P |
-s [-F]]
[-f | -iw]
[-hnv] source_file ...
target_dir |
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-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-P option.-P-L
option.-f-f option overrides any previous
-i and -w options.)-h-f option, to replace
a symlink which may point to a directory.-iln 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-h, for compatibility with other
ln implementations.-s-vln to be verbose, showing files as they are
processed.-wBy 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.
# ln -s /usr/src
/home/srcHard link /usr/local/bin/fooprog to file /usr/local/bin/fooprog-1.0:
# ln /usr/local/bin/fooprog-1.0
/usr/local/bin/fooprogAs 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.
-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.
ln utility conforms to IEEE Std
1003.2-1992 (“POSIX.2”).
ln command appeared in
Version 1 AT&T UNIX.
| April 20, 2017 | NetBSD 9.1 |