Nl (Unix)

Short description: Unix command

nlOperating 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.

## Contents

* 1 History
* 2 Syntax
* 3 Example
* 4 See also
* 5 References
* 6 External links

## History

`nl` 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

The following example numbers only the lines that begin with a capital letter A (matching on the regular expression /^A/). filename is optional.

$ nl -b p^A filename
apple
1  Apple
BANANA
2  Allspice
strawberry

It can be useful as an alternative to grep -n:

$ cat somefile
aaaa
bbbb
cccc
dddc
$ nl somefile | grep cccc
3 cccc

## See also

* wc (Unix) – the word count command
* cat (Unix) – concatenate command (-n flag is equivalent to nl -a)
* List of Unix commands

## References

1. ↑ `nl` – Commands & Utilities Reference, The Single UNIX Specification, Issue 7 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". http://unxutils.sourceforge.net/.

## External links

* v
* t
* e

Unix command-line interface programs and shell builtins

File system|

* cat
* 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
* sed
* sort
* strings
* tail
* tr
* 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

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