利用者:kusaReMKN/Nl (Unix)

nl

対応OS	Unix and Unix-like
プラットフォーム	Cross-platform
種別	Command
ライセンス	coreutils: GPLv3+

nl は、ファイルまたは標準入力からの入力に行番号を添えて標準出力に出力する Unix ユーティリティである。

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. It first appeared in System V release 2.

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

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