<s>
Quicksilver	B-Operating_System
is	O
a	O
utility	B-Application
app	I-Application
for	O
macOS	B-Application
.	O
</s>
<s>
Originally	O
developed	O
as	O
proprietary	B-License
freeware	I-License
by	O
Nicholas	O
Jitkoff	O
of	O
Blacktree	O
,	O
Inc.	O
,	O
it	O
is	O
now	O
an	O
open-source	B-Application
project	O
hosted	O
on	O
GitHub	B-Application
.	O
</s>
<s>
Quicksilver	B-Operating_System
is	O
essentially	O
a	O
graphical	O
shell	B-Operating_System
for	O
the	O
macOS	B-Application
operating	B-General_Concept
system	I-General_Concept
,	O
allowing	O
users	O
to	O
use	O
the	O
keyboard	O
to	O
rapidly	O
perform	O
tasks	O
such	O
as	O
launching	O
other	O
apps	O
,	O
manipulating	O
files	B-Operating_System
,	O
or	O
sending	O
e-mail	O
.	O
</s>
<s>
It	O
is	O
similar	O
to	O
the	O
macOS	B-Application
applications	O
LaunchBar	B-Operating_System
and	O
Alfred	B-Operating_System
,	O
but	O
uses	O
a	O
different	O
interaction	O
paradigm	O
.	O
</s>
<s>
Because	O
of	O
its	O
flexible	O
interface	O
and	O
extensibility	O
,	O
Quicksilver	B-Operating_System
has	O
been	O
called	O
one	O
of	O
the	O
top	O
productivity	O
applications	O
on	O
the	O
Mac	O
.	O
</s>
<s>
Invoked	O
with	O
a	O
keyboard	O
shortcut	O
,	O
Quicksilver	B-Operating_System
has	O
three	O
panes	O
,	O
into	O
which	O
the	O
user	O
can	O
enter	O
an	O
object	O
,	O
an	O
action	O
,	O
and	O
an	O
optional	O
attribute	O
—	O
analogous	O
to	O
creating	O
a	O
sentence	O
with	O
a	O
subject	O
,	O
verb	O
,	O
and	O
object	O
.	O
</s>
<s>
Quicksilver	B-Operating_System
is	O
a	O
background	O
application	O
that	O
runs	O
while	O
the	O
operating	B-General_Concept
system	I-General_Concept
is	O
running	O
,	O
maintaining	O
a	O
"	O
catalog	O
"	O
of	O
files	B-Operating_System
and	O
objects	O
on	O
the	O
user	O
's	O
computer	O
.	O
</s>
<s>
By	O
applying	O
incremental	B-Application
search	I-Application
as	O
the	O
user	O
types	O
,	O
Quicksilver	B-Operating_System
predicts	O
the	O
filename	O
or	O
action	O
typed	O
by	O
the	O
user	O
and	O
automatically	O
selects	O
the	O
object	O
.	O
</s>
<s>
Quicksilver	B-Operating_System
uses	O
a	O
priority	O
system	O
based	O
on	O
prior	O
usage	O
to	O
"	O
learn	O
"	O
the	O
user	O
's	O
habits	O
,	O
ultimately	O
requiring	O
only	O
a	O
few	O
letters	O
for	O
the	O
most	O
commonly	O
selected	O
objects	O
.	O
</s>
<s>
Quicksilver	B-Operating_System
allows	O
users	O
to	O
define	O
"	O
triggers	O
,	O
"	O
which	O
perform	O
a	O
specific	O
command	O
(	O
direct	O
object/action/indirect	O
object	O
combination	O
)	O
whenever	O
a	O
customizable	O
keyboard	O
shortcut	O
is	O
pressed	O
.	O
</s>
<s>
For	O
instance	O
,	O
if	O
a	O
command	O
opening	O
the	O
Documents	O
folder	O
is	O
bound	O
to	O
the	O
F7	B-Application
key	I-Application
,	O
this	O
hotkey	O
would	O
trigger	O
that	O
action	O
regardless	O
of	O
what	O
application	O
the	O
user	O
is	O
currently	O
in	O
.	O
</s>
<s>
Quicksilver	B-Operating_System
has	O
a	O
built-in	O
plug-in	B-Application
architecture	O
,	O
allowing	O
the	O
user	O
to	O
choose	O
and	O
install	O
plug-ins	B-Application
providing	O
integration	O
with	O
a	O
specific	O
program	O
,	O
interface	O
,	O
or	O
new	O
feature	O
.	O
</s>
<s>
For	O
example	O
,	O
plug-ins	B-Application
exist	O
for	O
sending	O
email	O
via	O
Mail	B-Operating_System
without	O
opening	O
the	O
application	O
or	O
manipulating	O
images	O
via	O
text	O
commands	O
.	O
</s>
<s>
Because	O
shell	B-Language
scripts	I-Language
and	O
AppleScripts	B-Application
can	O
be	O
stored	O
in	O
the	O
catalog	O
,	O
any	O
function	O
which	O
can	O
be	O
performed	O
with	O
a	O
script	O
can	O
be	O
tied	O
to	O
Quicksilver	B-Operating_System
through	O
either	O
the	O
command	B-Application
window	I-Application
or	O
triggers	O
.	O
</s>
<s>
Because	O
most	O
Apple-native	O
applications	O
have	O
extensive	O
scripting	O
libraries	O
,	O
many	O
common	O
tasks	O
can	O
easily	O
be	O
performed	O
from	O
Quicksilver	B-Operating_System
.	O
</s>
<s>
For	O
instance	O
,	O
iTunes	B-Operating_System
can	O
be	O
told	O
to	O
play	O
or	O
pause	O
,	O
increase	O
or	O
decrease	O
the	O
current	O
track	O
's	O
rating	O
,	O
or	O
skip	O
to	O
the	O
previous	O
or	O
next	O
track	O
.	O
</s>
<s>
There	O
are	O
various	O
visual	O
interfaces	O
for	O
Quicksilver	B-Operating_System
,	O
Constellation	O
Menus	O
supporting	O
mouse	O
gestures	O
,	O
and	O
a	O
Notification	O
Hub	O
which	O
supports	O
Growl	B-Operating_System
.	O
</s>
<s>
Experimental	O
trunk	B-General_Concept
builds	O
of	O
Quicksilver	B-Operating_System
,	O
known	O
as	O
Alchemy	O
,	O
have	O
many	O
major	O
changes	O
.	O
</s>
<s>
This	O
includes	O
extensions	O
and	O
core	O
functionality	O
that	O
most	O
applications	O
and	O
plugins	B-Application
will	O
use	O
.	O
</s>
<s>
β5X	O
Plugins	B-Application
are	O
incompatible	O
.	O
</s>
<s>
These	O
builds	O
have	O
four	O
major	O
components	O
:	O
Crucible	O
,	O
a	O
framework	O
with	O
extension	O
to	O
AppKit	B-Operating_System
and	O
tools	O
common	O
to	O
all	O
Alchemy	O
applications	O
;	O
elements	O
,	O
a	O
framework	O
supporting	O
the	O
plugin	B-Application
architecture	O
;	O
quicksilver	B-Operating_System
,	O
a	O
command	B-Application
window	I-Application
driven	O
launcher	O
;	O
and	O
catalyst	O
,	O
which	O
triggers	O
a	O
preference	O
pane	O
.	O
</s>
<s>
Nicholas	O
Jitkoff	O
started	O
development	O
of	O
Quicksilver	B-Operating_System
in	O
2003	O
.	O
</s>
<s>
He	O
released	O
several	O
versions	O
to	O
the	O
public	O
until	O
2006	O
and	O
maintained	O
an	O
internet	B-Application
forum	I-Application
for	O
the	O
tool	O
from	O
the	O
beginning	O
.	O
</s>
<s>
On	O
October	O
30	O
,	O
2007	O
,	O
the	O
source	O
code	O
for	O
Quicksilver	B-Operating_System
was	O
made	O
available	O
via	O
Google	B-Protocol
Code	I-Protocol
.	O
</s>
<s>
In	O
November	O
2009	O
,	O
development	O
shifted	O
to	O
using	O
GitHub	B-Application
.	O
</s>
<s>
Quicksilver	B-Operating_System
is	O
now	O
developed	O
by	O
a	O
team	O
of	O
volunteers	O
known	O
collectively	O
as	O
QSApp	O
.	O
</s>
<s>
At	O
the	O
end	O
of	O
2010	O
,	O
the	O
new	O
website	O
QSApp.com	O
was	O
launched	O
,	O
with	O
the	O
aim	O
of	O
unifying	O
and	O
collating	O
all	O
of	O
Quicksilver	B-Operating_System
's	O
fragmented	O
builds	O
,	O
plugins	B-Application
and	O
support	O
groups	O
.	O
</s>
<s>
Since	O
its	O
launch	O
,	O
the	O
site	O
has	O
included	O
a	O
new	O
Plugins	B-Application
Repository	O
,	O
Wiki	O
and	O
Downloads	O
section	O
.	O
</s>
<s>
On	O
March	O
25	O
,	O
2013	O
,	O
Quicksilver	B-Operating_System
v1.0	O
was	O
released	O
after	O
ten	O
years	O
of	O
beta	O
testing	O
.	O
</s>
<s>
On	O
March	O
25	O
,	O
2022	O
,	O
Quicksilver	B-Operating_System
v2.0	O
was	O
released	O
,	O
which	O
runs	O
natively	O
on	O
Apple	O
Silicon	O
(	O
M1	O
)	O
Macs	O
.	O
</s>
<s>
Quicksilver	B-Operating_System
's	O
icon	O
is	O
based	O
on	O
the	O
alchemical	O
symbol	O
for	O
mercury	O
,	O
"	O
quicksilver	B-Operating_System
"	O
being	O
an	O
archaic	O
name	O
for	O
the	O
element	O
.	O
</s>
