<s>
The	O
command	B-Application
is	O
a	O
standard	O
Unix	B-Application
command	I-Application
utility	O
used	O
to	O
create	O
a	O
hard	B-Application
link	I-Application
or	O
a	O
symbolic	B-Application
link	I-Application
(	O
symlink	B-Application
)	O
to	O
an	O
existing	O
file	B-Operating_System
or	O
directory	B-Application
.	O
</s>
<s>
The	O
use	O
of	O
a	O
hard	B-Application
link	I-Application
allows	O
multiple	O
filenames	B-Device
to	O
be	O
associated	O
with	O
the	O
same	O
file	B-Operating_System
since	O
a	O
hard	B-Application
link	I-Application
points	O
to	O
the	O
inode	B-Application
of	O
a	O
given	O
file	B-Operating_System
,	O
the	O
data	O
of	O
which	O
is	O
stored	O
on	O
disk	B-Device
.	O
</s>
<s>
On	O
the	O
other	O
hand	O
,	O
symbolic	B-Application
links	I-Application
are	O
special	O
files	O
that	O
refer	O
to	O
other	O
files	O
by	O
name	O
.	O
</s>
<s>
The	O
command	B-Application
by	O
default	O
creates	O
hard	B-Application
links	I-Application
,	O
and	O
when	O
called	O
with	O
the	O
command	B-Application
line	I-Application
parameter	O
creates	O
symbolic	B-Application
links	I-Application
.	O
</s>
<s>
Most	O
operating	B-General_Concept
systems	I-General_Concept
prevent	O
hard	B-Application
links	I-Application
to	O
directories	B-Application
from	O
being	O
created	O
since	O
such	O
a	O
capability	O
could	O
disrupt	O
the	O
structure	O
of	O
a	O
file	B-Application
system	I-Application
and	O
interfere	O
with	O
the	O
operation	O
of	O
other	O
utilities	O
.	O
</s>
<s>
The	O
command	B-Application
can	O
however	O
be	O
used	O
to	O
create	O
symbolic	B-Application
links	I-Application
to	O
non-existent	O
files	O
.	O
</s>
<s>
The	O
version	O
of	O
bundled	O
in	O
GNU	B-Application
coreutils	I-Application
was	O
written	O
by	O
Mike	O
Parker	O
and	O
David	O
MacKenzie	O
.	O
</s>
<s>
The	O
command	B-Application
is	O
available	O
as	O
a	O
separate	O
package	O
for	O
Microsoft	B-Application
Windows	I-Application
as	O
part	O
of	O
the	O
UnxUtils	B-Application
collection	O
of	O
native	B-Language
Win32	B-Library
ports	O
of	O
common	O
GNU	B-Operating_System
Unix-like	B-Operating_System
utilities	O
.	O
</s>
<s>
The	O
command	B-Application
has	O
also	O
been	O
ported	O
to	O
the	O
IBM	B-Application
i	I-Application
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Links	O
allow	O
more	O
than	O
one	O
filename	B-Device
to	O
refer	O
to	O
the	O
same	O
file	B-Operating_System
as	O
in	O
the	O
case	O
of	O
a	O
hard	B-Application
link	I-Application
or	O
act	O
as	O
pointers	O
to	O
a	O
filename	B-Device
as	O
in	O
the	O
case	O
of	O
a	O
soft	B-Application
link	I-Application
.	O
</s>
<s>
Both	O
hard	B-Application
links	I-Application
and	O
soft	B-Application
links	I-Application
can	O
be	O
created	O
by	O
the	O
command	B-Application
.	O
</s>
<s>
Hard	B-Application
links	I-Application
,	O
also	O
known	O
simply	O
as	O
links	O
,	O
are	O
objects	O
that	O
associate	O
the	O
filename	B-Device
with	O
the	O
inode	B-Application
,	O
and	O
therefore	O
the	O
file	B-Operating_System
contents	O
itself	O
.	O
</s>
<s>
A	O
given	O
file	B-Operating_System
on	O
disk	B-Device
could	O
have	O
multiple	O
links	O
scattered	O
through	O
the	O
directory	B-Architecture
hierarchy	I-Architecture
,	O
with	O
all	O
of	O
the	O
links	O
being	O
equivalent	O
since	O
they	O
all	O
associate	O
with	O
the	O
same	O
inode	B-Application
.	O
</s>
<s>
Creating	O
a	O
link	O
therefore	O
does	O
not	O
copy	O
the	O
contents	O
of	O
the	O
file	B-Operating_System
but	O
merely	O
causes	O
another	O
name	O
to	O
be	O
associated	O
with	O
the	O
same	O
contents	O
.	O
</s>
<s>
Each	O
time	O
a	O
hard	B-Application
link	I-Application
is	O
created	O
,	O
a	O
link	O
counter	O
that	O
is	O
a	O
part	O
of	O
the	O
inode	B-Application
structure	O
gets	O
incremented	O
;	O
a	O
file	B-Operating_System
is	O
not	O
deleted	O
until	O
its	O
reference	O
count	O
reaches	O
zero	O
.	O
</s>
<s>
However	O
,	O
hard	B-Application
links	I-Application
can	O
only	O
be	O
created	O
on	O
the	O
same	O
file	B-Application
system	I-Application
;	O
this	O
can	O
prove	O
to	O
be	O
a	O
disadvantage	O
.	O
</s>
<s>
Symbolic	B-Application
links	I-Application
are	O
special	O
files	O
which	O
,	O
when	O
encountered	O
during	O
pathname	B-Application
resolution	O
,	O
modify	O
the	O
to	O
be	O
taken	O
to	O
the	O
location	O
which	O
the	O
symbolic	B-Application
link	I-Application
contains	O
.	O
</s>
<s>
The	O
content	O
of	O
the	O
symbolic	B-Application
link	I-Application
is	O
therefore	O
the	O
destination	O
path	B-Application
string	O
,	O
which	O
can	O
also	O
be	O
examined	O
using	O
the	O
command	B-Application
line	I-Application
utility	O
.	O
</s>
<s>
The	O
symbolic	B-Application
link	I-Application
may	O
contain	O
an	O
arbitrary	O
string	O
which	O
does	O
not	O
refer	O
to	O
the	O
location	O
of	O
an	O
existing	O
file	B-Operating_System
.	O
</s>
<s>
Such	O
a	O
symbolic	B-Application
link	I-Application
will	O
fail	O
until	O
a	O
file	B-Operating_System
is	O
created	O
at	O
the	O
location	O
which	O
is	O
contained	O
by	O
the	O
symbolic	B-Application
link	I-Application
.	O
</s>
<s>
By	O
contrast	O
,	O
a	O
symbolic	B-Application
link	I-Application
to	O
an	O
existing	O
file	B-Operating_System
will	O
fail	O
if	O
the	O
existing	O
file	B-Operating_System
is	O
moved	O
to	O
a	O
different	O
location	O
(	O
or	O
renamed	O
)	O
.	O
</s>
<s>
The	O
utility	O
on	O
systems	O
compliant	O
with	O
the	O
Single	O
Unix	B-Application
Specification	O
is	O
specified	O
in	O
the	O
Shell	O
and	O
Utilities	O
(	O
XCU	O
)	O
document	O
,	O
which	O
forms	O
a	O
part	O
of	O
the	O
Single	O
Unix	B-Application
Specification	O
.	O
</s>
<s>
In	O
the	O
"	O
single	O
file	B-Operating_System
"	O
invocation	O
the	O
utility	O
creates	O
a	O
new	O
hard	B-Application
link	I-Application
(	O
directory	B-Application
entry	O
)	O
for	O
the	O
source	O
file	B-Operating_System
specified	O
by	O
the	O
operand	O
at	O
the	O
destination	O
path	B-Application
specified	O
by	O
the	O
operand	O
.	O
</s>
<s>
However	O
,	O
if	O
the	O
option	O
is	O
specified	O
,	O
a	O
symbolic	B-Application
link	I-Application
is	O
created	O
.	O
</s>
<s>
In	O
the	O
"	O
multiple	O
file	B-Operating_System
"	O
invocation	O
the	O
utility	O
creates	O
a	O
new	O
hard	B-Application
link	I-Application
(	O
)	O
,	O
or	O
if	O
the	O
option	O
is	O
specified	O
,	O
a	O
symbolic	B-Application
link	I-Application
,	O
for	O
each	O
file	B-Operating_System
specified	O
by	O
the	O
operand	O
,	O
at	O
a	O
destination	O
path	B-Application
in	O
an	O
existing	O
directory	B-Application
named	O
by	O
operand	O
.	O
</s>
<s>
The	O
specification	O
also	O
specifies	O
the	O
command	B-Application
line	I-Application
options	I-Application
that	O
must	O
be	O
supported	O
:	O
</s>
<s>
Force	O
existing	O
destination	O
pathnames	B-Application
to	O
be	O
removed	O
to	O
allow	O
the	O
link	O
.	O
</s>
<s>
For	O
each	O
operand	O
that	O
names	O
a	O
file	B-Operating_System
that	O
is	O
a	O
symbolic	B-Application
link	I-Application
,	O
create	O
a	O
hard	B-Application
link	I-Application
to	O
the	O
file	B-Operating_System
referenced	O
by	O
the	O
symbolic	B-Application
link	I-Application
.	O
</s>
<s>
For	O
each	O
operand	O
that	O
names	O
a	O
file	B-Operating_System
that	O
is	O
a	O
symbolic	B-Application
link	I-Application
,	O
create	O
a	O
(	O
hard	O
)	O
link	O
to	O
the	O
symbolic	B-Application
link	I-Application
itself	O
.	O
</s>
<s>
Create	O
symbolic	B-Application
links	I-Application
instead	O
of	O
hard	B-Application
links	I-Application
.	O
</s>
<s>
If	O
neither	O
target	O
file	B-Operating_System
nor	O
target	O
directory	B-Application
are	O
specified	O
,	O
links	O
will	O
be	O
created	O
in	O
the	O
current	B-Application
working	I-Application
directory	I-Application
.	O
</s>
