<s>
Files	B-Protocol
transferred	I-Protocol
over	I-Protocol
Shell	I-Protocol
protocol	I-Protocol
(	O
FISH	O
)	O
is	O
a	O
network	O
protocol	O
that	O
uses	O
Secure	B-Protocol
Shell	I-Protocol
(	O
SSH	B-Protocol
)	O
or	O
Remote	B-Protocol
Shell	I-Protocol
(	O
RSH	O
)	O
to	O
transfer	B-Protocol
files	I-Protocol
between	O
computers	O
and	O
manage	O
remote	O
files	O
.	O
</s>
<s>
The	O
advantage	O
of	O
FISH	O
is	O
that	O
all	O
it	O
requires	O
on	O
the	O
server-side	O
is	O
an	O
SSH	B-Protocol
or	O
RSH	O
implementation	O
,	O
Unix	B-Application
shell	I-Application
,	O
and	O
a	O
set	O
of	O
standard	O
Unix	B-Application
utilities	O
(	O
like	O
ls	B-Application
,	O
cat	B-Device
or	O
dd	B-Application
—	O
unlike	O
other	O
methods	O
of	O
remote	O
access	O
to	O
files	O
via	O
a	O
remote	B-Protocol
shell	I-Protocol
,	O
scp	B-Protocol
for	O
example	O
,	O
which	O
requires	O
scp	B-Protocol
on	O
the	O
server	O
side	O
)	O
.	O
</s>
<s>
Optionally	O
,	O
there	O
can	O
be	O
a	O
special	O
FISH	O
server	O
program	O
(	O
called	O
start_fish_server	O
)	O
on	O
the	O
server	O
,	O
which	O
executes	O
FISH	O
commands	O
instead	O
of	O
Unix	B-Application
shell	I-Application
and	O
thus	O
speeds	O
up	O
operations	O
.	O
</s>
<s>
The	O
protocol	O
was	O
designed	O
by	O
Czech	O
Linux	O
Kernel	O
Hacker	O
,	O
Pavel	O
Machek	O
,	O
in	O
1998	O
for	O
the	O
Midnight	B-Protocol
Commander	I-Protocol
software	O
tool	O
.	O
</s>
<s>
When	O
there	O
is	O
no	O
special	O
server	O
program	O
,	O
Unix	B-Application
shell	I-Application
ignores	O
the	O
fish	O
command	O
as	O
a	O
comment	O
and	O
executes	O
the	O
equivalent	O
shell	O
command(s )	O
.	O
</s>
<s>
Return	O
codes	O
are	O
a	O
superset	O
to	O
those	O
used	O
in	O
FTP	B-Protocol
.	O
</s>
<s>
The	O
client	O
initiates	O
SSH	B-Protocol
or	O
RSH	O
connection	O
with	O
echo	O
FISH	O
:	O
;	O
/bin/sh	O
as	O
the	O
command	O
executed	O
on	O
remote	O
machine	O
.	O
</s>
<s>
This	O
should	O
make	O
it	O
possible	O
for	O
the	O
server	O
to	O
distinguish	O
FISH	O
connections	O
from	O
normal	O
RSH	O
or	O
SSH	B-Protocol
.	O
</s>
<s>
The	O
first	O
two	O
commands	O
sent	O
to	O
the	O
server	O
are	O
FISH	O
and	O
VER	O
to	O
negotiate	O
FISH	B-Protocol
protocol	I-Protocol
,	O
its	O
version	O
and	O
extensions	O
.	O
</s>
<s>
which	O
indicates	O
supported	O
version	O
of	O
the	O
FISH	B-Protocol
protocol	I-Protocol
and	O
supported	O
extensions	O
.	O
</s>
<s>
tramp-fish.el	O
implemented	O
it	O
in	O
Emacs	O
TRAMP	O
(	O
but	O
might	O
if	O
nobody	O
needed	O
it	O
)	O
;	O
Emacs	O
TRAMP	O
in	O
overall	O
has	O
similar	O
goals	O
to	O
FISH	O
:	O
remote	O
access	O
to	O
files	O
through	O
a	O
remote	O
Unix	B-Application
shell	I-Application
.	O
</s>
