nl(1)nl(1)NAMEnl - Numbers lines in a file
SYNOPSISnl [-b type] [-d delimiter1[delimiter2]] [-f type] [-h type] [-i num‐
ber] [-l number] [-n format] [-p] [-s [separator]] [-vnumber] [-wnum‐
ber] [file]
STANDARDS
Interfaces documented on this reference page conform to industry stan‐
dards as follows:
nl: XCU5.0
Refer to the standards(5) reference page for more information about
industry standards and associated tags.
OPTIONS
Use the following options to change the default settings. Specifies
which body section lines to number. The recognized types are as fol‐
lows: Numbers all lines. Number only non-empty lines. Does not number
any lines. Numbers only those lines containing the specified pattern.
The full range of regular expressions is supported for pattern.
The default for type is t. Uses delimiter1 and delimiter2 as
the delimiters for the start of a logical page section. The
default characters are \: (backslash followed by a colon).
You can specify either one or two characters after the -d
option. If you want to use a backslash as a delimiter, enter
two backslashes (\\). If you specify only one character, it is
used as start of a logical page, and the end delimiter remains
the default. Specifies which logical page footer lines to num‐
ber. The types recognized are the same as in -b type.
The default for type is n. Specifies which logical page header
lines to number. The types recognized are the same as in -b
type.
The default for type is n. Increments logical page line numbers
by number. The default is 1. Counts number blank lines as 1.
You must use one or more of the “-ba”, “-fa”, and “-ha” options
with this option for it to be effective. For example, -l3 will
only number the third adjacent blank. The default is 1. Speci‐
fies format as the line numbering format. Recognized formats are
as follows: Left justified, leading zeroes are suppressed.
Right justified, leading zeroes are suppressed (default). Right
justified, leading zeroes are kept. Ignores logical page delim‐
iters (does not restart numbering). Separates text from line
numbers with the separator string. The default value of separa‐
tor is a tab character.
[Tru64 UNIX] If you enter -s without an argument, there is no
separation between the line number and its text. Sets the ini‐
tial logical page line number to number. Specifies number as
the number of digits in the line number. The default value of
number is 6.
OPERANDS
The path name of a file in which the lines are to be numbered. If file
is not specified, standard input is used.
DESCRIPTION
The nl command reads file (standard input by default), numbers the
lines in the input, and writes the numbered lines to standard output.
In the output, nl numbers the lines on the left, according to the
options 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 (sections can be empty). Unless
you use the -p option, nl resets the line numbers at the start of each
logical page. You can set line numbering options independently for the
header, body, and footer sections (for example, no numbering of header
and footer lines while numbering text lines only in the body).
Signal the start of logical page sections with lines in file that con‐
tain nothing but the following delimiter characters (assuming the
default delimiters--see the description of the -d option):
Line Contents Start of
\:\:\: Header
\:\: Body
\: Footer
You can name only one file on the command line. You can list the
options and the file name in any order.
EXIT STATUS
The following exit values are returned: Successful completion. An
error occurred.
EXAMPLES
To number only the nonblank lines, enter: nl chap1
This displays a numbered listing of chap1, numbering only the
nonblank lines in the body sections. If chap1 contains no \:\:\
:, \:\ :, or \: delimiters, then the entire file is considered
the body. To number all lines, enter: nl-ba chap1
This numbers all the lines in the body sections, including blank
lines. This form of the nl command is adequate for most uses.
To specify a different line number format, enter: nl-i10-nrz
-s:: -v10-w4 chap1
This numbers the lines of chap1, starting with 10 (-v10) and
counting by 10s (-i10). It displays four digits for each number
(-w4), including leading zeroes (-nrz). The line numbers are
separated from the text by two colons (-s::).
For example, if chap1 contains the following text:
A not-so-important note to remember:
You can't kill time without injuring eternity.
then the numbered listing is as follows:
0010::A not-so-important note to remember:
0020::You can't kill time without injuring eternity.
Notice that the blank line was not numbered. To do this, use the
-ba option as shown in Example 2.
ENVIRONMENT VARIABLES
The following environment variables affect the execution of nl: Pro‐
vides a default value for the internationalization variables that are
unset or null. If LANG is unset or null, the corresponding value from
the default locale is used. If any of the internationalization vari‐
ables contain an invalid setting, the utility behaves as if none of the
variables had been defined. If set to a non-empty string value, over‐
rides the values of all the other internationalization variables.
Determines the locale for the interpretation of sequences of bytes of
text data as characters (for example, single-byte as opposed to multi‐
byte characters in arguments and input files), the behavior of classes
within regular expressions, and for deciding which characters are in
character class graph. Determines the locale for the format and con‐
tents of diagnostic messages written to standard error. Determines the
location of message catalogues for the processing of LC_MESSAGES.
SEE ALSO
Commands: cat(1), pr(1)
Standards: standards(5)nl(1)
