1NL(P) POSIX Programmer's Manual NL(P)
2
6 nl - line numbering filter
7
9 nl [-p][-b type][-d delim][-f type][-h type][-i incr][-l num][-n for‐
10 mat]
11 [-s sep][-v startnum][-w width][file]
12
14 The nl utility shall read lines from the named file or the standard
15 input if no file is named and shall reproduce the lines to standard
16 output. Lines shall be numbered on the left. Additional functionality
17 may be provided in accordance with the command options in effect.
18 The nl utility views the text it reads in terms of logical pages. Line
20 numbering shall be reset at the start of each logical page. A logical
21 page consists of a header, a body, and a footer section. Empty sections
22 are valid. Different line numbering options are independently available
23 for header, body, and footer (for example, no numbering of header and
24 footer lines while numbering blank lines only in the body).
25 The starts of logical page sections shall be signaled by input lines
27 containing nothing but the following delimiter characters:
28 Line Start of
30 \:\:\: Header
31 \:\: Body
32 \: Footer
33 Unless otherwise specified, nl shall assume the text being read is in a
35 single logical page body.
36
38 The nl utility shall conform to the Base Definitions volume of
39 IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines. Only
40 one file can be named.
41 The following options shall be supported:
43 -b type
45 Specify which logical page body lines shall be numbered. Recog‐
46 nized types and their meaning are:
47 a
49 Number all lines.
50 t
52 Number only non-empty lines.
53 n
55 No line numbering.
56 pstring
58 Number only lines that contain the basic regular expression
59 specified in string.
60 The default type for logical page body shall be t (text lines num‐
63 bered).
64 -d delim
66 Specify the delimiter characters that indicate the start of a
67 logical page section. These can be changed from the default
68 characters "\:" to two user-specified characters. If only one
69 character is entered, the second character shall remain the
70 default character ':' .
71 -f type
73 Specify the same as b type except for footer. The default for
74 logical page footer shall be n (no lines numbered).
75 -h type
77 Specify the same as b type except for header. The default type
78 for logical page header shall be n (no lines numbered).
79 -i incr
81 Specify the increment value used to number logical page lines.
82 The default shall be 1.
83 -l num
85 Specify the number of blank lines to be considered as one. For
86 example, -l 2 results in only the second adjacent blank line
87 being numbered (if the appropriate -h a, -b a, or -f a option is
88 set). The default shall be 1.
89 -n format
91 Specify the line numbering format. Recognized values are: ln,
92 left justified, leading zeros suppressed; rn, right justified,
93 leading zeros suppressed; rz, right justified, leading zeros
94 kept. The default format shall be rn (right justified).
95 -p Specify that numbering should not be restarted at logical page
97 delimiters.
98 -s sep
100 Specify the characters used in separating the line number and
101 the corresponding text line. The default sep shall be a <tab>.
102 -v startnum
104 Specify the initial value used to number logical page lines. The
105 default shall be 1.
106 -w width
108 Specify the number of characters to be used for the line number.
109 The default width shall be 6.
110
113 The following operand shall be supported:
114 file A pathname of a text file to be line-numbered.
116
119 The standard input is a text file that is used if no file operand is
120 given.
121
123 The input file named by the file operand is a text file.
124
126 The following environment variables shall affect the execution of nl:
127 LANG Provide a default value for the internationalization variables
129 that are unset or null. (See the Base Definitions volume of
130 IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
131 ables for the precedence of internationalization variables used
132 to determine the values of locale categories.)
133 LC_ALL If set to a non-empty string value, override the values of all
135 the other internationalization variables.
136 LC_COLLATE
138 Determine the locale for the behavior of ranges, equivalence
140 classes, and multi-character collating elements within regular
141 expressions.
142 LC_CTYPE
144 Determine the locale for the interpretation of sequences of
145 bytes of text data as characters (for example, single-byte as
146 opposed to multi-byte characters in arguments and input files),
147 the behavior of character classes within regular expressions,
148 and for deciding which characters are in character class graph
149 (for the -b t, -f t, and -h t options).
150 LC_MESSAGES
152 Determine the locale that should be used to affect the format
153 and contents of diagnostic messages written to standard error.
154 NLSPATH
156 Determine the location of message catalogs for the processing of
157 LC_MESSAGES .
158
161 Default.
162
164 The standard output shall be a text file in the following format:
165 "%s%s%s", <line number>, <separator>, <input line>
168 where <line number> is one of the following numeric formats:
170 %6d When the rn format is used (the default; see -n).
172 %06d When the rz format is used.
174 %-6d When the ln format is used.
176 <empty>
178 When line numbers are suppressed for a portion of the page; the
179 <separator> is also suppressed.
180 In the preceding list, the number 6 is the default width; the -w option
183 can change this value.
184
186 The standard error shall be used only for diagnostic messages.
187
189 None.
190
192 None.
193
195 The following exit values shall be returned:
196 0 Successful completion.
198 >0 An error occurred.
200
203 Default.
204 The following sections are informative.
206
208 In using the -d delim option, care should be taken to escape characters
209 that have special meaning to the command interpreter.
210
212 The command:
213 nl -v 10 -i 10 -d \!+ file1
216 numbers file1 starting at line number 10 with an increment of 10. The
218 logical page delimiter is "!+" . Note that the '!' has to be escaped
219 when using csh as a command interpreter because of its history substi‐
220 tution syntax. For ksh and sh the escape is not necessary, but does not
221 do any harm.
222
224 None.
225
227 None.
228
230 pr
231
233 Portions of this text are reprinted and reproduced in electronic form
234 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
235 -- Portable Operating System Interface (POSIX), The Open Group Base
236 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
237 Electrical and Electronics Engineers, Inc and The Open Group. In the
238 event of any discrepancy between this version and the original IEEE and
239 The Open Group Standard, the original IEEE and The Open Group Standard
240 is the referee document. The original Standard can be obtained online
241 at http://www.opengroup.org/unix/online.html .
242IEEE/The Open Group 2003 NL(P)