nl(1) General Commands Manual nl(1)
Name
nl - line numbering filter
Syntax
nl [-h type] [-b type] [-f type] [-v start#] [-i incr] [-p ] [-l num] [-s sep] [-w width] [-n format] [-d delim] file
Description
The command reads lines from the named file or from the standard input, if no file is named, and reproduces the lines on the standard out-
put. Lines are numbered on the left in accordance with the command options in effect.
The command 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. Different line numbering options are independently avail-
able for header, body, and footer. For example, you can elect not to number header and footer lines while numbering blank lines in the
body.
The start of logical page sections is signaled by input lines containing nothing but the following delimiter characters:
Line contents Start of
::: header
:: body
: footer
Unless otherwise specified, assumes that the text it is reading is in the body of a single logical page.
Options
Command options may appear in any order and may be intermingled with an optional file name. Only one file may be named.
-b type Specifies which logical page body lines are to be numbered. The following are recognized types and their meaning: a,
number all lines; t, number lines with printable text only; n, no line numbering; pstring, number only lines that con-
tain the regular expression specified in string.
The default type for logical page body is t (text lines numbered).
-h type Same as -b type except for header. Default type for logical page header is n (no lines numbered).
-f type Same as -b type except for footer. Default for logical page footer is n (no lines numbered).
-p Do not restart numbering at logical page delimiters.
-v start# The initial value used to number logical page lines. Default is 1.
-i incr The increment value used to number logical page lines. Default is 1.
-s sep The character used in separating the line number and the corresponding text line. Default sep is a tab.
-w width The number of characters used for the line number. Default width is 6.
-n format The line numbering format. Recognized values are the following: ln, left justified, leading zeroes suppressed; rn,
right justified, leading zeroes suppressed; rz, right justified, leading zeroes kept. Default format is rn (right jus-
tified).
-l num The number of blank lines to be considered as one. For example, -l2 results in only the second adjacent blank being
numbered (if the appropriate -ha, -ba, or -fa option is set). Default is 1.
-d xx The delimiter characters specifying the start of a logical page section may be changed from the default characters (:)
to two user-specified characters. If only one character is entered, the second character remains the default character
(:). No space should appear between the -d and the delimiter characters. To enter a backslash, you must type two
backslashes (//).
Examples
nl -v10 -i10 -d!+ file1
This command numbers file1 starting at line number 10 with an increment of ten. The logical page delimiters are !+.
See Also
pr(1)
nl(1)