nl (Unix)

nl
Operating system	Unix and Unix-like
Platform	Cross-platform
Type	Command
License	coreutils: GPLv3+

nl is a Unix utility for numbering lines, either from a file or from standard input, reproducing output on standard output.

History

<syntaxhighlight lang="text" class="" style="" inline="1">nl</syntaxhighlight> is part of the X/Open Portability Guide since issue 2 of 1987. It was inherited into the first version of POSIX.1 and the Single Unix Specification.^[1] It first appeared in System V release 2.^[2]

The version of nl bundled in GNU coreutils was written by Scott Bartram and David MacKenzie.^[3]

The command is available as a separate package for Microsoft Windows as part of the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities.^[4]

Syntax

The command has a number of switches:

a - number all lines
t - number lines with printable text only
n - no line numbering
string - number only those lines containing the regular expression defined in the string supplied.

The default applied switch is t.

nl also supports some command line options.

Example

$ nl tf
    1  echo press cr
    2  read cr
    3  done

</syntaxhighlight> The following example numbers only the lines that begin with a capital letter A (matching on the regular expression /^A/). filename is optional. <syntaxhighlight lang="console"> $ nl -b p^A filename

      apple
   1  Apple
      BANANA
   2  Allspice
      strawberry

</syntaxhighlight> It can be useful as an alternative to grep -n: <syntaxhighlight lang="console"> $ cat somefile aaaa bbbb cccc dddc $ nl somefile | grep cccc

   3 cccc

</syntaxhighlight>

References

^ nl – Shell and Utilities Reference, The Single UNIX Specification, Version 4 from The Open Group
^ nl(1) – FreeBSD General Commands Manual
^ nl(1) – Linux General Commands Manual
^ "Native Win32 ports of some GNU utilities". unxutils.sourceforge.net.

External links

[1] nl – Shell and Utilities Reference, The Single UNIX Specification, Version 4 from The Open Group

[2] nl(1) – FreeBSD General Commands Manual

[3] nl(1) – Linux General Commands Manual

[4] "Native Win32 ports of some GNU utilities". unxutils.sourceforge.net.

[1]

[2]

[3]

[4]

v t e Unix command-line interface programs and shell builtins
File system	cat chattr chmod chown chgrp cksum cmp cp dd du df file fuser ln ls mkdir mv pax pwd rm rmdir split tee touch type umask
Processes	at bg crontab fg kill nice ps time
User environment	env exit logname mesg talk tput uname who write
Text processing	awk basename comm csplit cut diff dirname ed ex fold head iconv join m4 more nl paste patch printf read sed sort strings tail tr troff uniq vi wc xargs
Shell builtins	alias cd echo test unset wait
Searching	find grep
Documentation	man
Software development	ar ctags lex make nm strip yacc
Miscellaneous	bc cal expr lp od sleep true and false
Categories Standard Unix programs Unix SUS2008 utilities List

v t e GNU Core Utilities command-line interface programs
File system	chcon chmod chown chgrp cksum cp dd df dir dircolors install ln ls mkdir mkfifo mknod mktemp mv realpath rm rmdir shred sync touch truncate vdir
Text utilities	b2sum base32 base64 cat cksum comm csplit cut expand fmt fold head join md5sum nl numfmt od paste ptx pr sha1sum shuf sort split sum tac tail tr tsort unexpand uniq wc
Shell utilities	arch basename chroot date dirname du echo env expr factor false groups hostid id link logname nice nohup nproc pathchk pinky printenv printf pwd readlink runcon seq sleep stat stdbuf stty tee test timeout true tty uname unlink uptime users who whoami yes

History

Syntax

Example

See also

References

External links