<s>
unexpand	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
.	O
</s>
<s>
Here	O
the	O
echo	B-Application
command	I-Application
prints	O
a	O
string	O
of	O
text	O
that	O
includes	O
multiple	O
consecutive	O
spaces	O
,	O
then	O
the	O
output	O
is	O
directed	O
into	O
the	O
unexpand	B-Device
command	B-Application
.	O
</s>
<s>
The	O
resulting	O
output	O
is	O
then	O
displayed	O
by	O
the	O
octal	O
dump	O
command	B-Application
od	B-Device
.	O
</s>
<s>
At	O
the	O
second	O
prompt	O
,	O
the	O
same	O
echo	B-Application
output	O
is	O
sent	O
directly	O
through	O
the	O
od	B-Device
command	B-Application
.	O
</s>
<s>
As	O
can	O
be	O
seen	O
by	O
comparing	O
the	O
two	O
,	O
the	O
unexpand	B-Device
program	O
converts	O
sequences	O
of	O
eight	O
spaces	O
into	O
single	O
tabs	O
(	O
printed	O
as	O
'	O
\t	O
 '	O
)	O
.	O
</s>
