<s>
The	O
remote	B-Protocol
shell	I-Protocol
(	O
rsh	O
)	O
is	O
a	O
command-line	B-Application
computer	B-Application
program	I-Application
that	O
can	O
execute	O
shell	O
commands	O
as	O
another	O
user	O
,	O
and	O
on	O
another	O
computer	O
across	O
a	O
computer	B-Architecture
network	I-Architecture
.	O
</s>
<s>
The	O
remote	O
system	O
to	O
which	O
rsh	O
connects	O
runs	O
the	O
rsh	B-Protocol
daemon	I-Protocol
(	O
rshd	B-Protocol
)	O
.	O
</s>
<s>
The	O
daemon	B-Operating_System
typically	O
uses	O
the	O
well-known	O
Transmission	B-Protocol
Control	I-Protocol
Protocol	I-Protocol
(	O
TCP	O
)	O
port	B-Protocol
number	I-Protocol
514	O
.	O
</s>
<s>
Rsh	O
originated	O
as	O
part	O
of	O
the	O
BSD	B-Operating_System
Unix	I-Operating_System
operating	B-General_Concept
system	I-General_Concept
,	O
along	O
with	O
rcp	B-Application
,	O
as	O
part	O
of	O
the	O
rlogin	B-Application
package	O
on	O
4.2BSD	O
in	O
1983	O
.	O
rsh	O
has	O
since	O
been	O
ported	O
to	O
other	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
The	O
rsh	O
command	O
has	O
the	O
same	O
name	O
as	O
another	O
common	O
UNIX	O
utility	O
,	O
the	O
restricted	B-Operating_System
shell	I-Operating_System
,	O
which	O
first	O
appeared	O
in	O
PWB/UNIX	B-Operating_System
;	O
in	O
System	B-Operating_System
V	I-Operating_System
Release	I-Operating_System
4	I-Operating_System
,	O
the	O
restricted	B-Operating_System
shell	I-Operating_System
is	O
often	O
located	O
at	O
/usr/bin/rsh	O
.	O
</s>
<s>
As	O
described	O
in	O
the	O
rlogin	B-Application
article	O
,	O
the	O
rsh	O
protocol	O
is	O
not	O
secure	O
for	O
network	O
use	O
,	O
because	O
it	O
sends	O
unencrypted	O
information	O
over	O
the	O
network	O
,	O
among	O
other	O
reasons	O
.	O
</s>
<s>
rsh	O
has	O
largely	O
been	O
replaced	O
with	O
the	O
secure	B-Protocol
shell	I-Protocol
(	O
ssh	B-Protocol
)	O
program	O
,	O
even	O
on	O
local	O
networks	O
.	O
</s>
<s>
If	O
no	O
command	O
is	O
specified	O
then	O
rsh	O
will	O
log	O
in	O
on	O
the	O
remote	O
system	O
using	O
rlogin	B-Application
.	O
</s>
<s>
The	O
network	O
location	O
of	O
the	O
remote	O
computer	O
is	O
looked	O
up	O
using	O
the	O
Domain	B-Protocol
Name	I-Protocol
System	I-Protocol
.	O
</s>
