<s>
Capistrano	B-Application
is	O
an	O
open-source	B-Application
tool	O
for	O
running	O
scripts	O
on	O
multiple	O
servers	O
;	O
its	O
main	O
use	O
is	O
deploying	O
web	B-Application
applications	I-Application
.	O
</s>
<s>
It	O
automates	O
the	O
process	O
of	O
making	O
a	O
new	O
version	O
of	O
an	O
application	O
available	O
on	O
one	O
or	O
more	O
web	B-Application
servers	I-Application
,	O
including	O
supporting	O
tasks	O
such	O
as	O
changing	O
databases	O
.	O
</s>
<s>
Capistrano	B-Application
is	O
written	O
in	O
the	O
Ruby	B-Language
language	I-Language
and	O
is	O
distributed	O
using	O
the	O
RubyGems	B-Application
distribution	O
channel	O
.	O
</s>
<s>
It	O
is	O
an	O
outgrowth	O
of	O
the	O
Ruby	B-Application
on	I-Application
Rails	I-Application
web	B-Application
application	I-Application
framework	O
,	O
but	O
it	O
is	O
also	O
used	O
to	O
deploy	O
web	B-Application
applications	I-Application
written	O
using	O
other	O
languages	O
,	O
for	O
example	O
,	O
PHP	B-Application
.	O
</s>
<s>
Capistrano	B-Application
is	O
implemented	O
primarily	O
for	O
use	O
on	O
the	O
UNIX	B-Application
shell	I-Application
command	O
line	O
.	O
</s>
<s>
A	O
user	O
may	O
choose	O
from	O
many	O
Capistrano	B-Application
recipes	O
,	O
e.g.	O
</s>
<s>
to	O
deploy	O
current	O
changes	O
to	O
the	O
web	B-Application
application	I-Application
or	O
roll	O
back	O
to	O
the	O
previous	O
deployment	O
state	O
.	O
</s>
<s>
Originally	O
called	O
SwitchTower	O
,	O
the	O
name	O
was	O
changed	O
to	O
Capistrano	B-Application
in	O
March	O
2006	O
due	O
to	O
a	O
trademark	O
conflict	O
.	O
</s>
<s>
Capistrano	B-Application
is	O
a	O
utility	O
and	O
framework	O
for	O
executing	O
commands	O
in	O
parallel	O
on	O
multiple	O
remote	O
machines	O
,	O
via	O
SSH	O
.	O
</s>
<s>
It	O
uses	O
a	O
simple	O
domain-specific	B-Language
language	I-Language
borrowed	O
in	O
part	O
from	O
the	O
tool	O
Rake	B-Application
.	O
</s>
<s>
Capistrano	B-Application
was	O
originally	O
designed	O
to	O
simplify	O
and	O
automate	O
deployment	O
of	O
web	B-Application
applications	I-Application
to	O
distributed	O
environments	O
,	O
and	O
originally	O
came	O
bundled	O
with	O
a	O
set	O
of	O
tasks	O
designed	O
for	O
deploying	O
Ruby	B-Application
on	I-Application
Rails	I-Application
applications	O
.	O
</s>
<s>
The	O
deployment	O
tasks	O
are	O
now	O
(	O
as	O
of	O
Capistrano	B-Application
2.0	O
)	O
opt-in	O
and	O
require	O
clients	O
to	O
explicitly	O
put	O
"	O
load	O
'	O
deploy	O
 '	O
"	O
in	O
their	O
recipes	O
.	O
</s>
<s>
Assuming	O
the	O
capfile	B-Application
is	O
in	O
the	O
current	O
directory	O
,	O
the	O
user	O
would	O
execute	O
that	O
task	O
like	O
this	O
:	O
</s>
