Numbers lines in a file.
The nl command reads the File parameter (standard input by default), numbers the lines in the input, and writes the numbered lines to standard output. In the output, the nl command numbers the lines on the left according to the flags you specify on the command line.
The input text must be written in logical pages. Each logical page has a header, a body, and a footer section (you can have empty sections). Unless you use the -p flag, the nl command resets the line numbers at the start of each logical page. You can set line-numbering flags independently for the header, body, and footer sections (for example, the header and footer lines can be numbered while the text lines are not).
Signal the start of logical-page sections with lines in the file that contain only the following delimiter characters:
|Line Contents||Start Of|
You can name only one file on the command line. You can list the flags and the file name in any order.
All the parameters are set by default. Use the following flags to change these default settings. Except for the -s flag, enter a -n flag without a variable to see its default value.
|-b Type|| Chooses which body section lines to number. Recognized values
for the Type variable are:
|-d Delimiter||Uses the two characters specified by the Delimiter variable as the delimiters for the start of a logical page section. The default characters are \: (backslash, colon). You may specify two ASCII characters, two 1-byte extended characters, or one extended character. If you enter only one 1-byte character after the -d flag, the second character remains the default (a colon). If you want to use a backslash as a delimiter, enter two backslashes (\\).|
|-f Type||Chooses which logical-page footer lines to number. The possible values for the Type variable are the same as the -b flag. The default value of the Type variable is n (no lines numbered).|
|-h Type||Chooses which logical-page header lines to number. The possible values for the Type variable are the same as the -b flag. The default value of the Type variables n (no lines numbered).|
|-i Number||Increments logical-page line numbers by the number specified in the Number variable. The default value of the Number variable is 1. The range of the Number variable is from 1 to 250.|
|-l Number||(Lowercase L) Uses the value specified in the Number parameter as the number of blank lines to count as one. For example, -l3 numbers every third blank line in a series. The default value of the Number variable is 1. This flag works when the -ha, -ba, or -fa option is set. The range of the Number variable is from 1 to 250.|
|-n Format|| Uses the value of the Format variable as the line
numbering format. Recognized formats are:
|-p||Does not restart numbering at logical page delimiters.|
|-s Separator||Separates the text from its line number with the character specified in the Separator variable. The default value of the Separator variable is a tab character.|
|-v Number||Sets the initial logical-page line number to the value specified by the Number variable. The default value of the Number variable is 1. The range of the Number variable is from 0 to 32767.|
|-w Number||Uses the value specified by the Number variable as the number of characters in the line number. The default value of the Number variable is 6. The range of the Number variable is from 1 to 20.|
This command returns the following exit values:
|>0||An error occurred.|
- To number only the non-blank
This displays a numbered listing of chap1, numbering only the non-blank lines in the body sections. If chap1 contains no \:\:\+:, or \: delimiters, then the entire file is considered the body.
- To number all lines:
This numbers all the lines in the body sections, including blank lines. This form of the nl command is adequate for most uses.
nl -ba chap1
- To specify a different
line number format, enter:
This numbers the lines of chap1 starting with ten (-v10) and counting by tens (-i10). It displays four digits for each number (-w4), including leading zeros (-nrz). The line numbers are separated from the text by two colons (-s : :).
nl -i10 -nrz -s:: -v10 -w4 chap1
For example, if chap1 contains the text:
then the numbered listing is:
A not-so-important note to remember: You can't kill time without injuring eternity.
Note that the blank line was not numbered. To do this, use the -ba flag as shown in example 2.
0010::A not-so-important 0020::note to remember 0030::You can't kill time 0040::without injuring eternity.
|/usr/bin/nl||Contains the nl command.|