nl

nl [options] [file]

Number the lines of file in logical page segments. Numbering resets to 1 at the start of each logical page. Pages consist of a header, body, and footer; each section may be empty. It is the body that gets numbered. The sections are delimited by special standalone lines as indicated next; the delimiter lines are copied to the output as empty lines.

Section Delimiters

\:\:\:	Start of header
\:\:	Start of body
\:	Start of footer

Options

-btype

Number lines according to type. Values are:

a	All lines.
n	No lines.
t	Text lines only (the default).
p"exp"	Lines matching the regular expression exp only.

-dxy

Use characters xy to delimit logical pages (default is \:).

-ftype

Like -b, but number footer (default type is n).

-htype

Like -b, but number header (default type is n).

-in

Increment each line number by n (default is 1).

-ln

Count n consecutive blank lines as one line.

-nformat

Set line number format. Values are:

ln	Left-justify, omit leading zeros.
rn	Right-justify, omit leading zeros (default).
rz	Right-justify.

-p

Do not reset numbering at start of pages.

-sc

Separate text from line number with character(s) c (default is a tab).

-vn

Number each page starting at n (default is 1).

-wn

Use n columns to show line number (default is 6).

Examples

List the current directory, numbering files as 1), 2), etc.:

ls | nl -w3 -s')  '

Number C source code and save it:

nl prog.c > print_prog

Number only lines that begin with #include:

nl -bp"^#include" prog.c