nl(1)nl(1)NAMEnl - line numbering filter
SYNOPSIS
type] type] type] start#] incr] sep] width] format] num] delim] [file]
DESCRIPTION
reads lines from the named file or the standard input if no file is
named and reproduces the lines on the standard output. Lines are num‐
bered on the left in accordance with the command options in effect.
views the text it reads in terms of logical pages. Line numbering is
reset at the start of each logical page. A logical page consists of a
header, a body, and a footer section. Empty sections are valid. Dif‐
ferent line numbering options are independently available for header,
body, and footer (e.g., no numbering of header and footer lines while
numbering blank lines only in the body).
The start of logical page sections are signaled by input lines contain‐
ing nothing but the following delimiter character(s):
│
Line contents │ Start of
──────────────┼──────────
\:\:\: │ header
\:\: │ body
\: │ footer
Unless told otherwise, assumes the text being read is in a single logi‐
cal page body.
Command options can appear in any order and can be intermingled with an
optional file name. Only one file can be named. recognizes the fol‐
lowing options:
Specifies which logical page body lines are to be numbered.
Recognized types and their meanings are:
number all lines;
number lines with printable text only;
no line numbering;
number only lines that contain the regular
expression
specified in string. Basic Regular
Expression syntax is supported (see
regexp(5)).
The default type for logical page body is (text
lines numbered).
Same as except for header. Default type for logical page
header is (no lines numbered).
Same as except for footer. Default for logical page footer
is (no lines numbered).
Do not restart numbering at logical page delimiters.
start# is the initial value used to number logical page
lines. Default is
incr is the increment value used to number logical page
lines. Default is
sep is the character or characters used in separating
the line number and the corresponding text line.
Default sep is a tab.
width is the number of character columns to be used for
the line number. Default width is
format is the line numbering format. Recognized values
are:
left justified, leading zeroes
suppressed;
right justified,
leading zeroes suppressed;
right justified, leading zeroes kept.
Default format is (right justified).
num is the number of consecutive blank lines to be
treated and numbered as a single line. For example,
results in every third adjacent blank line being
numbered if the appropriate and/or option is set.
Default is
The delimiter characters specifying the start of a logical page
section can be changed from the default characters
to two user-specified characters. If only one char‐
acter is entered, the second character remains the
default character No space should appear between the
and the delimiter characters, however, this restric‐
tion is not there for (see standards(5)) compliant
To define a backslash as the delimiter, use two
backslashes.
EXTERNAL INFLUENCES
For information about the UNIX Standard environment, see standards(5).
Environment Variables
determines the collating sequence used in evaluating regular expres‐
sions.
determines the characters matched by character class expressions in
regular expressions.
If or is not specified in the environment or is set to the empty
string, the value of is used as a default for each unspecified or empty
variable. If is not specified or is set to the empty string, a default
of "C" (see lang(5)) is used instead of
If any internationalization variable contains an invalid setting,
behaves as if all internationalization variables are set to "C". See
environ(5).
International Code Set Support
Single-byte character code sets are supported.
EXAMPLES
Number starting at line number 10, using an increment of ten. The log‐
ical page delimiters are and
SEE ALSOpr(1), environ(5), lang(5), regexp(5), standards(5).
STANDARDS CONFORMANCEnl(1)