运维经–目录

nl给你的文本增加行号

nl,在Linux系统中计算文件内容行号.
nl命令 读取 file 参数（缺省情况下标准输入），计算输入中的行号，将计算过的行号写入标准输出。在输出中，nl命令根据您在命令行中指定的标志来计算左边的行。输入文本必须写在逻辑页中。每个逻辑页有头、主体和页脚节（可以有空节）。除非使用-p选项，nl 命令在每个逻辑页开始的地方重新设置行号。可以单独为头、主体和页脚节设置行计算标志（例如，头和页脚行可以被计算然而文本行不能）。其默认的结果与cat -n有点不太一样， nl 可以将行号做比较多的显示设计，包括位数与是否自动补齐0等等的功能。

使用

Usage: nl [OPTION]... [FILE]...
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 separating logical pages
  -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 at logical pages
  -s, --number-separator=STRING   add STRING after (possible) line number
  -v, --starting-line-number=NUMBER  first line number on each logical page
  -w, --number-width=NUMBER       use NUMBER columns for line numbers
      --help     display this help and exit
      --version  output version information and exit

By default, selects -v1 -i1 -l1 -sTAB -w6 -nrn -hn -bt -fn.  CC are
two delimiter characters for separating logical pages, a missing
second character implies :.  Type \\ for \.  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

例子

1.显示文件内容 相当于 cat -n

# cat -n pwd.txt
[frank@LAPTOP-0OCJTGJR ~]$ cat -n pwd.txt
     1  root:x:0:0:root:/root:/bin/bash
     2  bin:x:1:1:bin:/bin:/sbin/nologin
     3
     4  daemon:x:2:2:daemon:/sbin:/sbin/nologin
     5
     6  adm:x:3:4:adm:/var/adm:/sbin/nologin
# nl
[frank@LAPTOP-0OCJTGJR ~]$ nl pwd.txt
     1  root:x:0:0:root:/root:/bin/bash
     2  bin:x:1:1:bin:/bin:/sbin/nologin

     3  daemon:x:2:2:daemon:/sbin:/sbin/nologin

     4  adm:x:3:4:adm:/var/adm:/sbin/nologin

2.空行不显示行号-b t

[frank@LAPTOP-0OCJTGJR ~]$ nl -b t pwd.txt
     1  root:x:0:0:root:/root:/bin/bash
     2  bin:x:1:1:bin:/bin:/sbin/nologin

     3  daemon:x:2:2:daemon:/sbin:/sbin/nologin

     4  adm:x:3:4:adm:/var/adm:/sbin/nologin

3.行号左对齐-n ln

[frank@LAPTOP-0OCJTGJR ~]$ nl -b t -n ln pwd.txt
1       root:x:0:0:root:/root:/bin/bash
2       bin:x:1:1:bin:/bin:/sbin/nologin

3       daemon:x:2:2:daemon:/sbin:/sbin/nologin

4       adm:x:3:4:adm:/var/adm:/sbin/nologin

4.行号右对齐（默认）-n rn

[frank@LAPTOP-0OCJTGJR ~]$ nl -b t -n rn pwd.txt
     1  root:x:0:0:root:/root:/bin/bash
     2  bin:x:1:1:bin:/bin:/sbin/nologin

     3  daemon:x:2:2:daemon:/sbin:/sbin/nologin

     4  adm:x:3:4:adm:/var/adm:/sbin/nologin

5.行号右对齐补0（6位长）-n rz

[frank@LAPTOP-0OCJTGJR ~]$ nl -b t -n rz pwd.txt
000001  root:x:0:0:root:/root:/bin/bash
000002  bin:x:1:1:bin:/bin:/sbin/nologin

000003  daemon:x:2:2:daemon:/sbin:/sbin/nologin

000004  adm:x:3:4:adm:/var/adm:/sbin/nologin

6.行号右对齐补0（指定长度-w 2）

[frank@LAPTOP-0OCJTGJR ~]$ nl -b t -n rz -w 2 pwd.txt
01      root:x:0:0:root:/root:/bin/bash
02      bin:x:1:1:bin:/bin:/sbin/nologin

03      daemon:x:2:2:daemon:/sbin:/sbin/nologin

04      adm:x:3:4:adm:/var/adm:/sbin/nologin