NL(1)							    BSD General Commands Manual 						     NL(1)

NAME

     nl -- line numbering filter

SYNOPSIS

     nl [-p] [-b type] [-d delim] [-f type] [-h type] [-i incr] [-l num] [-n format] [-s sep] [-v startnum] [-w width] [file]

DESCRIPTION

     The nl utility reads lines from the named file or the standard input if the file argument is omitted, applies a configurable line numbering
     filter operation and writes the result to the standard output.

     The nl utility treats the text it reads in terms of logical pages.  Unless specified otherwise, 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 available for header, body and footer sections.

     The starts of logical page sections are signaled by input lines containing nothing but one of the following sequences of delimiter charac-
     ters:

	   Line       "Start of"
	   :::     header
	   ::       body
	   :	      footer

     If the input does not contain any logical page section signaling directives, the text being read is assumed to consist of a single logical
     page body.

     The following options are available:

     -b type
	     Specify the logical page body lines to be numbered.  Recognized type arguments are:

	     a		Number all lines.

	     t		Number only non-empty lines.

	     n		No line numbering.

	     pexpr	Number only those lines that contain the basic regular expression specified by expr.

	     The default type for logical page body lines is t.

     -d delim
	     Specify the delimiter characters used to indicate the start of a logical page section in the input file.  At most two characters may
	     be specified; if only one character is specified, the first character is replaced and the second character remains unchanged.  The
	     default delim characters are ``:''.

     -f type
	     Specify the same as -b type except for logical page footer lines.	The default type for logical page footer lines is n.

     -h type
	     Specify the same as -b type except for logical page header lines.	The default type for logical page header lines is n.

     -i incr
	     Specify the increment value used to number logical page lines.  The default incr value is 1.

     -l num  If numbering of all lines is specified for the current logical section using the corresponding -b a, -f a or -h a option, specify the
	     number of adjacent blank lines to be considered as one.  For example, -l 2 results in only the second adjacent blank line being num-
	     bered.  The default num value is 1.

     -n format
	     Specify the line numbering output format.	Recognized format arguments are:
	     ln    Left justified.
	     rn    Right justified, leading zeros suppressed.
	     rz    Right justified, leading zeros kept.

	     The default format is rn.

     -p      Specify that line numbering should not be restarted at logical page delimiters.

     -s sep  Specify the characters used in separating the line number and the corresponding text line.  The default sep setting is a single tab
	     character.

     -v startnum
	     Specify the initial value used to number logical page lines; see also the description of the -p option.  The default startnum value
	     is 1.

     -w width
	     Specify the number of characters to be occupied by the line number; in case the width is insufficient to hold the line number, it
	     will be truncated to its width least significant digits.  The default width is 6.

EXIT STATUS

     The nl utility exits 0 on success, and >0 if an error occurs.

SEE ALSO

     pr(1)

STANDARDS

     The nl utility conforms to X/Open Portability Guide Issue 4, Version 2 (``XPG4.2'') with the exception of not supporting the intermingling of
     the file operand with the options, which the standard considers an obsolescent feature to be removed from a further issue.

HISTORY

     The nl utility first appeared in AT&T System V Release 2 UNIX.

BSD
								 February 15, 1999							       BSD