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Linux / Unix Command: nl
Command Library
nl [-h header-style] [-b body-style] [-f footer-style] [-p] [-d cc] [-v start-number] [-i increment] [-l lines] [-s line-separator] [-w line-no-width] [-n {ln,rn,rz}] [--header-numbering=style] [--body-numbering=style] [--footer-numbering=style] [--first-page=number] [--page-increment=number] [--no-renumber] [--join-blank-lines=number] [--number-separator=string] [--number-width=number] [--number-format={ln,rn,rz}] [--section-delimiter=cc] [--help] [--version] [file...]
nl copies each specified file to the standard output, with line numbers added to the lines. The line number is reset to 1 at the top of each logical page. nl treats all of the input files as a single document and does not reset line numbers or logical pages between files. A logical page consists of: header, body, and footer.

The beginnings of the sections of logical pages are indicated in the input file by a line containing nothing except one of the following delimiter strings:

\:\:\: start of header
\:\: start of body
\: start of footer

The section delimiter strings are replaced by an empty line on output. Any text that comes before the first section delimiter string in the input file is considered to be part of a body section, so a file that does not contain any section delimiter strings is considered to consist of a single body section.

-h, --header-numbering=style
See --footer-numbering.

-b, --body-numbering=style
See --footer-numbering.

-f, --footer-numbering=style
Select the numbering style for lines in the footer section of each logical page. When a line is not numbered, the current line number is not incremented, but the line number separator character is still prepended to the line. The styles are:

number all lines

number only nonempty lines (default for body)

number no lines (default for header and

number only lines that contain a match for regexp

-p, --no-renumber
Do not reset the line number at the start of a logical page.

-v, --first-page=number
Set the initial line number on each logical page to number (default 1).

-i, --page-increment=number
Increment line numbers by number (default 1).

-l, --join-blank-lines=number
Consider number (default 1) consecutive empty lines to be one logical line for numbering, and only number the last one. Where fewer than number consecutive empty lines occur, do not number them. An empty line is one that contains no characters, not even spaces or tabs.

-s, --number-separator=string
Separate the line number from the text line in the output with string (default is a TAB character).

-w, --number-width=number
Use number characters for line numbers (default 6).

-n, --number-format={ln,rn,rz}
Select the line numbering format:

  • ln left justified, no leading zeros
  • rn right justified, no leading zeros (default)
  • rz right justified, leading zeros

-d, --section-delimiter=cc
Set the two delimiter characters that indicate the beginnings of logical page sections; if only one is given, the second remains ':'. To enter '\', use '\\'.

Print a usage message and exit with a status code indicating success.

Print version information on standard output then exit.


% nl myfile > myfile_lines_numbered

numbers the lines in the file myfile and puts the output to the file myfiles_lines_numbered.

Important: Use the man command (% man) to see how a command is used on your particular computer.

>> Linux Command Library Index

>> Also see Shell Command Library

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