<s>
In	O
computing	O
,	O
touch	O
is	O
a	O
command	B-Application
used	O
to	O
update	O
the	O
access	O
date	O
and/or	O
modification	O
date	O
of	O
a	O
computer	B-Operating_System
file	I-Operating_System
or	O
directory	B-Application
.	O
</s>
<s>
It	O
is	O
included	O
in	O
Unix	B-Application
and	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
,	O
TSC	O
's	O
FLEX	B-Device
,	O
Digital	O
Research/Novell	O
DR	B-Application
DOS	I-Application
,	O
the	O
AROS	B-Application
shell	O
,	O
the	O
Microware	B-Operating_System
OS-9	B-Operating_System
shell	O
,	O
and	O
ReactOS	B-Application
.	O
</s>
<s>
The	O
command	B-Application
is	O
also	O
available	O
for	O
FreeDOS	B-Application
and	O
Microsoft	B-Application
Windows	I-Application
.	O
</s>
<s>
Instead	O
it	O
simply	O
updates	O
the	O
dates	O
associated	O
with	O
the	O
file	O
or	O
directory	B-Application
.	O
</s>
<s>
An	O
updated	O
access	O
or	O
modification	O
date	O
can	O
be	O
important	O
for	O
a	O
variety	O
of	O
other	O
programs	O
such	O
as	O
backup	B-Protocol
utilities	O
or	O
the	O
make	B-Application
command-line	B-Application
interface	I-Application
programming	O
utility	O
.	O
</s>
<s>
The	O
touch	O
command	B-Application
can	O
also	O
be	O
useful	O
for	O
quickly	O
creating	O
files	O
for	O
programs	O
or	O
scripts	O
that	O
require	O
a	O
file	O
with	O
a	O
specific	O
name	O
to	O
exist	O
for	O
successful	O
operation	O
of	O
the	O
program	O
,	O
but	O
do	O
not	O
require	O
the	O
file	O
to	O
have	O
any	O
specific	O
content	O
.	O
</s>
<s>
The	O
Single	O
Unix	B-Application
Specification	O
(	O
SUS	O
)	O
specifies	O
that	O
touch	O
should	O
change	O
the	O
access	O
times	O
,	O
modification	O
times	O
,	O
or	O
both	O
,	O
for	O
a	O
file	O
.	O
</s>
<s>
A	O
touch	O
utility	O
first	O
appeared	O
in	O
Version	B-Operating_System
7	I-Operating_System
AT&T	B-Operating_System
UNIX	I-Operating_System
.	O
</s>
<s>
Today	O
,	O
the	O
command	B-Application
is	O
available	O
for	O
a	O
number	O
of	O
different	O
operating	B-General_Concept
systems	I-General_Concept
,	O
including	O
many	O
Unix	B-Application
and	O
Unix-like	B-Operating_System
systems	I-Operating_System
,	O
DOS	B-Device
,	O
Microsoft	B-Application
Windows	I-Application
and	O
the	O
classic	B-Application
Mac	I-Application
OS	I-Application
.	O
</s>
<s>
The	O
version	O
of	O
touch	O
bundled	O
in	O
GNU	B-Application
coreutils	I-Application
was	O
written	O
by	O
Paul	O
Rubin	O
,	O
Arnold	O
Robbins	O
,	O
Jim	O
Kingdon	O
,	O
David	O
MacKenzie	O
,	O
and	O
Randy	O
Smith	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
FreeDOS	B-Application
version	O
was	O
developed	O
by	O
Kris	O
Heidenstrom	O
and	O
is	O
licensed	O
under	O
the	O
GPL	B-License
.	O
</s>
<s>
DR	B-Application
DOS	I-Application
6.0	O
and	O
KolibriOS	B-Operating_System
include	O
an	O
implementation	O
of	O
the	O
command	B-Application
.	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>
