nl

qdisc -{add|list|delete} - Manage queueing disciplines

TLDR

Number non-blank lines in a file

$ nl [path/to/file]

Read from standard output

$ cat [path/to/file] | nl [options] -

Number only the lines with printable text

$ nl -t [path/to/file]

Number all lines including blank lines

$ nl -b a [path/to/file]

Number only the body lines that match a basic regular expression (BRE) pattern

$ nl -b p'FooBar[0-9]' [path/to/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

REPORTING BUGS

GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Report any translation bugs to <https://translationproject.org/team/>

COPYRIGHT

Copyright © 2022 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.

AUTHOR

Written by Scott Bartram and David MacKenzie.

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