<s>
In	O
computing	O
,	O
tty	B-Device
is	O
a	O
command	B-Application
in	O
Unix	B-Application
and	O
Unix-like	B-Operating_System
operating	I-Operating_System
systems	I-Operating_System
to	O
print	O
the	O
file	O
name	O
of	O
the	O
terminal	O
connected	O
to	O
standard	O
input	O
.	O
</s>
<s>
tty	B-Device
stands	O
for	O
TeleTYpewriter	O
.	O
</s>
<s>
The	O
tty	B-Device
command	B-Application
is	O
commonly	O
used	O
to	O
check	O
if	O
the	O
output	O
medium	O
is	O
a	O
terminal	O
.	O
</s>
<s>
The	O
command	B-Application
prints	O
the	O
file	O
name	O
of	O
the	O
terminal	O
connected	O
to	O
standard	O
input	O
.	O
</s>
<s>
If	O
no	O
file	O
is	O
detected	O
(	O
in	O
case	O
,	O
it	O
's	O
being	O
run	O
as	O
part	O
of	O
a	O
script	O
or	O
the	O
command	B-Application
is	O
being	O
piped	B-Operating_System
)	O
"	O
not	O
a	O
tty	B-Device
"	O
is	O
printed	O
to	O
stdout	O
and	O
the	O
command	B-Application
exits	O
with	O
an	O
exit	O
status	O
of	O
1	O
.	O
</s>
<s>
The	O
command	B-Application
also	O
can	O
be	O
run	O
in	O
silent	O
mode	O
(	O
tty	B-Device
-s	O
)	O
where	O
no	O
output	O
is	O
produced	O
,	O
and	O
the	O
command	B-Application
exits	O
with	O
an	O
appropriate	O
exit	O
status	O
.	O
</s>
