NL(1)

NAME
nl - number lines of files

SYNOPSIS
nl [OPTION]... [FILE]...

DESCRIPTION

Write each FILE to standard output, with line numbers added.

With no FILE, or when FILE is -, read standard input.

Mandatory arguments to long options are mandatory for short options too.

-b, --body-numbering=STYLE
    use STYLE for numbering body lines

-d, --section-delimiter=CC
    use CC for logical page delimiters

-f, --footer-numbering=STYLE
    use STYLE for numbering footer lines

-h, --header-numbering=STYLE
    use STYLE for numbering header lines

-i, --line-increment=NUMBER
    line number increment at each line

-l, --join-blank-lines=NUMBER
    group of NUMBER empty lines counted as one

-n, --number-format=FORMAT
    insert line numbers according to FORMAT

-p, --no-renumber
    do not reset line numbers for each section

-s, --number-separator=STRING
    add STRING after (possible) line number

-v, --starting-line-number=NUMBER
    first line number for each section

-w, --number-width=NUMBER
    use NUMBER columns for line numbers

--help
    display this help and exit

--version
    output version information and exit

Default options are: -bt -d'\:' -fn -hn -i1 -l1 -n'rn' -s<TAB> -v1 -w6

CC are two delimiter characters used to construct logical page delimiters; a missing second character implies ':'. As a GNU extension one can specify more than two characters, and also specifying the empty string (-d '') disables section matching.

STYLE is one of:

a   number all lines

t   number only nonempty lines

n   number no lines

pBRE
    number only lines that contain a match for the basic regular expression, BRE

FORMAT is one of:

ln  left justified, no leading zeros

rn  right justified, no leading zeros

rz  right justified, leading zeros

AUTHOR
Written by Scott Bartram and David MacKenzie.

REPORTING BUGS
Report bugs to: bug-coreutils@gnu.org
GNU coreutils home page: <https://www.gnu.org/software/coreutils/>
General help using GNU software: <https://www.gnu.org/gethelp/>
Report any translation bugs to <https://translationproject.org/team/>

COPYRIGHT
Copyright © 2026 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

SEE ALSO
Full documentation <https://www.gnu.org/software/coreutils/nl>
or available locally via: info '(coreutils) nl invocation'