<s>
as	O
is	O
a	O
generic	O
command	O
name	O
for	O
an	O
assembler	O
on	O
Unix	B-Application
.	O
</s>
<s>
More	O
than	O
one	O
assembler	O
for	O
Unix	B-Application
and	O
Unix-like	O
operating	O
systems	O
has	O
been	O
implemented	O
with	O
an	O
executable	O
called	O
as	O
.	O
</s>
<s>
As	O
of	O
November	O
1971	O
,	O
an	O
assembler	O
invoked	O
as	O
as	O
was	O
available	O
for	O
Unix	B-Application
.	O
</s>
<s>
Implemented	O
by	O
Bell	O
Labs	O
staff	O
,	O
it	O
was	O
based	O
upon	O
the	O
Digital	O
Equipment	O
Corporation	O
's	O
PAL-11R	B-Device
assembler	O
.	O
</s>
<s>
Circa	O
1986	O
,	O
the	O
GNU	B-Application
Assembler	I-Application
(	O
"	O
GAS	O
"	O
)	O
became	O
available	O
.	O
</s>
<s>
As	O
with	O
the	O
original	O
UNIX	B-Application
assembler	O
,	O
GAS	O
's	O
executable	O
is	O
simply	O
named	O
as	O
.	O
</s>
