<s>
nl	B-Device
is	O
a	O
Unix	B-Application
utility	I-Application
for	O
numbering	O
lines	O
,	O
either	O
from	O
a	O
file	O
or	O
from	O
standard	O
input	O
,	O
reproducing	O
output	O
on	O
standard	O
output	O
.	O
</s>
<s>
It	O
was	O
inherited	O
into	O
the	O
first	O
version	O
of	O
POSIX.1	O
and	O
the	O
Single	O
Unix	B-Application
Specification	O
.	O
</s>
<s>
It	O
first	O
appeared	O
in	O
System	B-Operating_System
V	I-Operating_System
release	O
2	O
.	O
</s>
<s>
The	O
version	O
of	O
nl	B-Device
bundled	O
in	O
GNU	B-Application
coreutils	I-Application
was	O
written	O
by	O
Scott	O
Bartram	O
and	O
David	O
MacKenzie	O
.	O
</s>
<s>
The	O
command	B-Application
is	O
available	O
as	O
a	O
separate	O
package	O
for	O
Microsoft	B-Application
Windows	I-Application
as	O
part	O
of	O
the	O
UnxUtils	B-Application
collection	O
of	O
native	B-Language
Win32	B-Library
ports	O
of	O
common	O
GNU	B-Operating_System
Unix-like	B-Operating_System
utilities	O
.	O
</s>
<s>
The	O
command	B-Application
has	O
a	O
number	O
of	O
switches	O
:	O
</s>
<s>
string	O
-	O
number	O
only	O
those	O
lines	O
containing	O
the	O
regular	B-Language
expression	I-Language
defined	O
in	O
the	O
string	O
supplied	O
.	O
</s>
<s>
nl	B-Device
also	O
supports	O
some	O
command	B-Application
line	O
options	O
.	O
</s>
<s>
The	O
following	O
example	O
numbers	O
only	O
the	O
lines	O
that	O
begin	O
with	O
a	O
capital	O
letter	O
A	O
(	O
matching	O
on	O
the	O
regular	B-Language
expression	I-Language
/	O
^	O
A/	O
)	O
.	O
</s>
