[unix-history] / usr / share / man / cat1 / sed.0

SED(1)                       BSD Reference Manual                       SED(1)

N\bNA\bAM\bME\bE
     s\bse\bed\bd - stream editor

S\bSY\bYN\bNO\bOP\bPS\bSI\bIS\bS
     s\bse\bed\bd [-\b-a\ban\bn] _\bc_\bo_\bm_\bm_\ba_\bn_\bd [_\bf_\bi_\bl_\be _\b._\b._\b.]
     s\bse\bed\bd [-\b-a\ban\bn] [-\b-e\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd] [-\b-f\bf _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b__\bf_\bi_\bl_\be] [_\bf_\bi_\bl_\be _\b._\b._\b.]

D\bDE\bES\bSC\bCR\bRI\bIP\bPT\bTI\bIO\bON\bN
     The s\bse\bed\bd utility reads the specified files, or the standard input if no
     files are specified, modifying the input as specified by a list of com-
     mands.  The input is then written to the standard output.

     A single command may be specified as the first argument to s\bse\bed\bd. Multiple
     commands may be specified by using the -\b-e\be or -\b-f\bf options.  All commands
     are applied to the input in the order they are specified regardless of
     their origin.

     The following options are available:

     -\b-a\ba      The files listed as parameters for the ``w'' functions are creat-
             ed (or truncated) before any processing begins, by default.  The
             -\b-a\ba option causes s\bse\bed\bd to delay opening each file until a command
             containing the related ``w'' function is applied to a line of in-
             put.

     -\b-e\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd
             Append the editing commands specified by the _\bc_\bo_\bm_\bm_\ba_\bn_\bd argument to
             the list of commands.

     -\b-f\bf _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b__\bf_\bi_\bl_\be
             Append the editing commands found in the file _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b__\bf_\bi_\bl_\be to the
             list of commands.  The editing commands should each be listed on
             a separate line.

     -\b-n\bn      By default, each line of input is echoed to the standard output
             after all of the commands have been applied to it.  The -\b-n\bn option
             suppresses this behavior.

     The form of a s\bse\bed\bd command is as follows:

           [address[,address]]function[arguments]

     Whitespace may be inserted before the first address and the function por-
     tions of the command.

     Normally, s\bse\bed\bd cyclically copies a line of input, not including its termi-
     nating newline character, into a _\bp_\ba_\bt_\bt_\be_\br_\bn _\bs_\bp_\ba_\bc_\be, (unless there is some-
     thing left after a ``D'' function), applies all of the commands with ad-
     dresses that select that pattern space, copies the pattern space to the
     standard output, appending a newline, and deletes the pattern space.

     Some of the functions use a _\bh_\bo_\bl_\bd _\bs_\bp_\ba_\bc_\be to save all or part of the pattern
     space for subsequent retrieval.

S\bSe\bed\bd A\bAd\bdd\bdr\bre\bes\bss\bse\bes\bs
     An address is not required, but if specified must be a number (that
     counts input lines cumulatively across input files), a dollar (``$'')
     character that addresses the last line of input, or a context address
     (which consists of a regular expression preceded and followed by a delim-
     iter).

     A command line with no addresses selects every pattern space.


     A command line with one address selects all of the pattern spaces that
     match the address.

     A command line with two addresses selects the inclusive range from the
     first pattern space that matches the first address through the next pat-
     tern space that matches the second.  (If the second address is a number
     less than or equal to the line number first selected, only that line is
     selected.)  Starting at the first line following the selected range, s\bse\bed\bd
     starts looking again for the first address.

     Editing commands can be applied to non-selected pattern spaces by use of
     the exclamation character (``!'') function.

S\bSe\bed\bd R\bRe\beg\bgu\bul\bla\bar\br E\bEx\bxp\bpr\bre\bes\bss\bsi\bio\bon\bns\bs
     The s\bse\bed\bd regular expressions are basic regular expressions (BRE's, see
     regex(3) for more information).  In addition, s\bse\bed\bd has the following two
     additions to BRE's:

     1.   In a context address, any character other than a backslash (``\'')
          or newline character may be used to delimit the regular expression.
          Also, putting a backslash character before the delimiting character
          causes the character to be treated literally.  For example, in the
          context address \xabc\xdefx, the RE delimiter is an ``x'' and the
          second ``x'' stands for itself, so that the regular expression is
          ``abcxdef''.

     2.   The escape sequence \n matches a newline character embedded in the
          pattern space.  You can't, however, use a literal newline character
          in an address or in the substitute command.

     One special feature of s\bse\bed\bd regular expressions is that they can default
     to the last regular expression used.  If a regular expression is empty,
     i.e. just the delimiter characters are specified, the last regular ex-
     pression encountered is used instead.  The last regular expression is de-
     fined as the last regular expression used as part of an address or sub-
     stitute command, and at run-time, not compile-time.  For example, the
     command ``/abc/s//XXX/'' will substitute ``XXX'' for the pattern ``abc''.

S\bSe\bed\bd F\bFu\bun\bnc\bct\bti\bio\bon\bns\bs
     In the following list of commands, the maximum number of permissible ad-
     dresses for each command is indicated by [0addr], [1addr], or [2addr],
     representing zero, one, or two addresses.

     The argument _\bt_\be_\bx_\bt consists of one or more lines.  To embed a newline in
     the text, precede it with a backslash.  Other backslashes in text are
     deleted and the following character taken literally.

     The ``r'' and ``w'' functions take an optional file parameter, which
     should be separated from the function letter by white space.  Each file
     given as an argument to s\bse\bed\bd is created (or its contents truncated) before
     any input processing begins.

     The ``b'', ``r'', ``s'', ``t'', ``w'', ``y'', ``!'', and ``:'' functions
     all accept additional arguments.  The following synopses indicate which
     arguments have to be separated from the function letters by white space
     characters.

     Two of the functions take a function-list.  This is a list of s\bse\bed\bd func-
     tions separated by newlines, as follows:

           { function
             function
             ...
             function
           }

     The ``{'' can be preceded by white space and can be followed by white
     space.  The function can be preceded by white space.  The terminating
     ``}'' must be preceded by a newline an optional white space.

     [2addr] function-list
             Execute function-list only when the pattern space is selected.

     [1addr]a\
     text
             Write _\bt_\be_\bx_\bt to standard output immediately before each attempt to
             read a line of input, whether by executing the ``N'' function or
             by beginning a new cycle.

     [2addr]b[lable]
             Branch to the ``:'' function with the specified label.  If the
             label is not specified, branch to the end of the script.

     [2addr]c\
     text
             Delete the pattern space.  With 0 or 1 address or at the end of a
             2-address range, _\bt_\be_\bx_\bt is written to the standard output.

     [2addr]d
             Delete the pattern space and start the next cycle.

     [2addr]D
             Delete the initial segment of the pattern space through the first
             newline character and start the next cycle.

     [2addr]g
             Replace the contents of the pattern space with the contents of
             the hold space.

     [2addr]G
             Append a newline character followed by the contents of the hold
             space to the pattern space.

     [2addr]h
             Replace the contents of the hold space with the contents of the
             pattern space.

     [2addr]H
             Append a newline character followed by the contents of the pat-
             tern space to the hold space.

     [1addr]i\
     text
             Write _\bt_\be_\bx_\bt to the standard output.

     [2addr]l
             (The letter ell.)  Write the pattern space to the standard output
             in a visually unambiguous form.  This form is as follows:

                   backslash          \
                   alert              \a
                   form-feed          \f
                   newline            \n
                   carriage-return    \r
                   tab                \t
                   vertical tab       \v

             Nonprintable characters are written as three-digit octal numbers
             (with a preceding backslash) for each byte in the character (most
             significant byte first).  Long lines are folded, with the point
             of folding indicated by displaying a backslash followed by a new-
             line.  The end of each line is marked with a ``$''.

     [2addr]n
             Write the pattern space to the standard output if the default
             output has not been suppressed, and replace the pattern space
             with the next line of input.

     [2addr]N
             Append the next line of input to the pattern space, using an em-
             bedded newline character to separate the appended material from
             the original contents.  Note that the current line number
             changes.

     [2addr]p
             Write the pattern space to standard output.

     [2addr]P
             Write the pattern space, up to the first newline character to the
             standard output.

     [1addr]q
             Branch to the end of the script and quit without starting a new
             cycle.

     [1addr]r file
             Copy the contents of _\bf_\bi_\bl_\be to the standard output immediately be-
             fore the next attempt to read a line of input.  If _\bf_\bi_\bl_\be cannot be
             read for any reason, it is silently ignored and no error condi-
             tion is set.

     [2addr]s/regular expression/replacement/flags
             Substitute the replacement string for the first instance of the
             regular expression in the pattern space.  Any character other
             than backslash or newline can be used instead of a slash to de-
             limit the RE and the replacement.  Within the RE and the replace-
             ment, the RE delimiter itself can be used as a literal character
             if it is preceded by a backslash.

             An ampersand (``&'') appearing in the replacement is replaced by
             the string matching the RE.  The special meaning of ``&'' in this
             context can be suppressed by preceding it by backslash.  The
             string ``\#'', where ``#'' is a digit, is replaced by the text
             matched by the corresponding backreference expression (see
             re_format(7)).

             A line can be split by substituting a newline character into it.
             To specify a newline character in the replacement string, precede
             it with a backslash.

             The value of _\bf_\bl_\ba_\bg_\bs in the substitute function is zero or more of
             the following:

                   0 ... 9
                           Make the substitution only for the N'th occurrence
                           of the regular expression in the pattern space.

                   g       Make the substitution for all non-overlapping
                           matches of the regular expression, not just the
                           first one.

                   p       Write the pattern space to standard output if a re-
                           placement was made.  If the replacement string is
                           identical to that which it replaces, it is still
                           considered to have been a replacement.

                   w _\bf_\bi_\bl_\be  Append the pattern space to _\bf_\bi_\bl_\be if a replacement
                           was made.  If the replacement string is identical
                           to that which it replaces, it is still considered
                           to have been a replacement.

     [2addr]t [label]
             Branch to the ``'': function bearing the label if any substitu-
             tions have been made since the most recent reading of an input
             line or execution of a ``t'' function.  If no label is specified,
             branch to the end of the script.

     [2addr]w _\bf_\bi_\bl_\be
             Append the pattern space to the _\bf_\bi_\bl_\be.

     [2addr]x
             Swap the contents of the pattern and hold spaces.

     [2addr]y/string1/string2/
             Replace all occurrences of characters in _\bs_\bt_\br_\bi_\bn_\bg_\b1 in the pattern
             space with the corresponding characters from _\bs_\bt_\br_\bi_\bn_\bg_\b2. Any charac-
             ter other than a backslash or newline can be used instead of a
             slash to delimit the strings.  Within _\bs_\bt_\br_\bi_\bn_\bg_\b1 and _\bs_\bt_\br_\bi_\bn_\bg_\b2, a
             backslash followed by any character other than a newline is that
             literal character, and a backslash followed by an ``n'' is re-
             placed by a newline character.

     [2addr]!function
     [2addr]!function-list
             Apply the function or function-list only to the lines that are
             _\bn_\bo_\bt selected by the address(es).

     [0addr]:label
             This function does nothing; it bears a label to which the ``b''
             and ``t'' commands may branch.

     [1addr]=
             Write the line number to the standard output followed by a new-
             line character.

     [0addr]
             Empty lines are ignored.

     [0addr]#
             The ``#'' and the remainder of the line are ignored (treated as a
             comment), with the single exception that if the first two charac-
             ters in the file are ``#n'', the default output is suppressed.
             This is the same as specifying the -\b-n\bn option on the command line.

     The s\bse\bed\bd utility exits 0 on success and >0 if an error occurs.

S\bSE\bEE\bE A\bAL\bLS\bSO\bO
     awk(1),  ed(1),  grep(1),  regex(3),  re_format(7)

H\bHI\bIS\bST\bTO\bOR\bRY\bY
     A s\bse\bed\bd command appeared in Version 7 AT&T UNIX.

S\bST\bTA\bAN\bND\bDA\bAR\bRD\bDS\bS
     The s\bse\bed\bd function is expected to be a superset of the IEEE Std1003.2
     (``POSIX'') specification.

4.4BSD                           June 6, 1993                                5
Commit	Line	Data
22072751 C	1	SED(1) BSD Reference Manual SED(1)
	2
	3	N\bNA\bAM\bME\bE
	4	s\bse\bed\bd - stream editor
	5
	6	S\bSY\bYN\bNO\bOP\bPS\bSI\bIS\bS
	7	s\bse\bed\bd [-\b-a\ban\bn] _\bc_\bo_\bm_\bm_\ba_\bn_\bd [_\bf_\bi_\bl_\be _\b._\b._\b.]
	8	s\bse\bed\bd [-\b-a\ban\bn] [-\b-e\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd] [-\b-f\bf _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b__\bf_\bi_\bl_\be] [_\bf_\bi_\bl_\be _\b._\b._\b.]
	9
	10	D\bDE\bES\bSC\bCR\bRI\bIP\bPT\bTI\bIO\bON\bN
	11	The s\bse\bed\bd utility reads the specified files, or the standard input if no
	12	files are specified, modifying the input as specified by a list of com-
	13	mands. The input is then written to the standard output.
	14
	15	A single command may be specified as the first argument to s\bse\bed\bd. Multiple
	16	commands may be specified by using the -\b-e\be or -\b-f\bf options. All commands
	17	are applied to the input in the order they are specified regardless of
	18	their origin.
	19
	20	The following options are available:
	21
	22	-\b-a\ba The files listed as parameters for the ``w'' functions are creat-
	23	ed (or truncated) before any processing begins, by default. The
	24	-\b-a\ba option causes s\bse\bed\bd to delay opening each file until a command
	25	containing the related ``w'' function is applied to a line of in-
	26	put.
	27
	28	-\b-e\be _\bc_\bo_\bm_\bm_\ba_\bn_\bd
	29	Append the editing commands specified by the _\bc_\bo_\bm_\bm_\ba_\bn_\bd argument to
	30	the list of commands.
	31
	32	-\b-f\bf _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b__\bf_\bi_\bl_\be
	33	Append the editing commands found in the file _\bc_\bo_\bm_\bm_\ba_\bn_\bd_\b__\bf_\bi_\bl_\be to the
	34	list of commands. The editing commands should each be listed on
	35	a separate line.
	36
	37	-\b-n\bn By default, each line of input is echoed to the standard output
	38	after all of the commands have been applied to it. The -\b-n\bn option
	39	suppresses this behavior.
	40
	41	The form of a s\bse\bed\bd command is as follows:
	42
	43	[address[,address]]function[arguments]
	44
	45	Whitespace may be inserted before the first address and the function por-
	46	tions of the command.
	47
	48	Normally, s\bse\bed\bd cyclically copies a line of input, not including its termi-
	49	nating newline character, into a _\bp_\ba_\bt_\bt_\be_\br_\bn _\bs_\bp_\ba_\bc_\be, (unless there is some-
	50	thing left after a ``D'' function), applies all of the commands with ad-
	51	dresses that select that pattern space, copies the pattern space to the
	52	standard output, appending a newline, and deletes the pattern space.
	53
	54	Some of the functions use a _\bh_\bo_\bl_\bd _\bs_\bp_\ba_\bc_\be to save all or part of the pattern
	55	space for subsequent retrieval.
	56
	57	S\bSe\bed\bd A\bAd\bdd\bdr\bre\bes\bss\bse\bes\bs
	58	An address is not required, but if specified must be a number (that
	59	counts input lines cumulatively across input files), a dollar (``$'')
	60	character that addresses the last line of input, or a context address
	61	(which consists of a regular expression preceded and followed by a delim-
	62	iter).
	63
	64	A command line with no addresses selects every pattern space.
65
66
67	A command line with one address selects all of the pattern spaces that
68	match the address.
69
70	A command line with two addresses selects the inclusive range from the
71	first pattern space that matches the first address through the next pat-
72	tern space that matches the second. (If the second address is a number
73	less than or equal to the line number first selected, only that line is
74	selected.) Starting at the first line following the selected range, s\bse\bed\bd
75	starts looking again for the first address.
76
77	Editing commands can be applied to non-selected pattern spaces by use of
78	the exclamation character (``!'') function.
79
80	S\bSe\bed\bd R\bRe\beg\bgu\bul\bla\bar\br E\bEx\bxp\bpr\bre\bes\bss\bsi\bio\bon\bns\bs
81	The s\bse\bed\bd regular expressions are basic regular expressions (BRE's, see
82	regex(3) for more information). In addition, s\bse\bed\bd has the following two
83	additions to BRE's:
84
85	1. In a context address, any character other than a backslash (``\'')
86	or newline character may be used to delimit the regular expression.
87	Also, putting a backslash character before the delimiting character
88	causes the character to be treated literally. For example, in the
89	context address \xabc\xdefx, the RE delimiter is an ``x'' and the
90	second ``x'' stands for itself, so that the regular expression is
91	``abcxdef''.
92
93	2. The escape sequence \n matches a newline character embedded in the
94	pattern space. You can't, however, use a literal newline character
95	in an address or in the substitute command.
96
97	One special feature of s\bse\bed\bd regular expressions is that they can default
98	to the last regular expression used. If a regular expression is empty,
99	i.e. just the delimiter characters are specified, the last regular ex-
100	pression encountered is used instead. The last regular expression is de-
101	fined as the last regular expression used as part of an address or sub-
102	stitute command, and at run-time, not compile-time. For example, the
103	command ``/abc/s//XXX/'' will substitute ``XXX'' for the pattern ``abc''.
104
105	S\bSe\bed\bd F\bFu\bun\bnc\bct\bti\bio\bon\bns\bs
106	In the following list of commands, the maximum number of permissible ad-
107	dresses for each command is indicated by [0addr], [1addr], or [2addr],
108	representing zero, one, or two addresses.
109
110	The argument _\bt_\be_\bx_\bt consists of one or more lines. To embed a newline in
111	the text, precede it with a backslash. Other backslashes in text are
112	deleted and the following character taken literally.
113
114	The ``r'' and ``w'' functions take an optional file parameter, which
115	should be separated from the function letter by white space. Each file
116	given as an argument to s\bse\bed\bd is created (or its contents truncated) before
117	any input processing begins.
118
119	The ``b'', ``r'', ``s'', ``t'', ``w'', ``y'', ``!'', and ``:'' functions
120	all accept additional arguments. The following synopses indicate which
121	arguments have to be separated from the function letters by white space
122	characters.
123
124	Two of the functions take a function-list. This is a list of s\bse\bed\bd func-
125	tions separated by newlines, as follows:
126
127	{ function
128	function
129	...
130	function
131	}
132
133	The ``{'' can be preceded by white space and can be followed by white
134	space. The function can be preceded by white space. The terminating
135	``}'' must be preceded by a newline an optional white space.
136
137	[2addr] function-list
138	Execute function-list only when the pattern space is selected.
139
140	[1addr]a\
141	text
142	Write _\bt_\be_\bx_\bt to standard output immediately before each attempt to
143	read a line of input, whether by executing the ``N'' function or
144	by beginning a new cycle.
145
146	[2addr]b[lable]
147	Branch to the ``:'' function with the specified label. If the
148	label is not specified, branch to the end of the script.
149
150	[2addr]c\
151	text
152	Delete the pattern space. With 0 or 1 address or at the end of a
153	2-address range, _\bt_\be_\bx_\bt is written to the standard output.
154
155	[2addr]d
156	Delete the pattern space and start the next cycle.
157
158	[2addr]D
159	Delete the initial segment of the pattern space through the first
160	newline character and start the next cycle.
161
162	[2addr]g
163	Replace the contents of the pattern space with the contents of
164	the hold space.
165
166	[2addr]G
167	Append a newline character followed by the contents of the hold
168	space to the pattern space.
169
170	[2addr]h
171	Replace the contents of the hold space with the contents of the
172	pattern space.
173
174	[2addr]H
175	Append a newline character followed by the contents of the pat-
176	tern space to the hold space.
177
178	[1addr]i\
179	text
180	Write _\bt_\be_\bx_\bt to the standard output.
181
182	[2addr]l
183	(The letter ell.) Write the pattern space to the standard output
184	in a visually unambiguous form. This form is as follows:
185
186	backslash \
187	alert \a
188	form-feed \f
189	newline \n
190	carriage-return \r
191	tab \t
192	vertical tab \v
193
194	Nonprintable characters are written as three-digit octal numbers
195	(with a preceding backslash) for each byte in the character (most
196	significant byte first). Long lines are folded, with the point
197	of folding indicated by displaying a backslash followed by a new-
198	line. The end of each line is marked with a ``$''.
199
200	[2addr]n
201	Write the pattern space to the standard output if the default
202	output has not been suppressed, and replace the pattern space
203	with the next line of input.
204
205	[2addr]N
206	Append the next line of input to the pattern space, using an em-
207	bedded newline character to separate the appended material from
208	the original contents. Note that the current line number
209	changes.
210
211	[2addr]p
212	Write the pattern space to standard output.
213
214	[2addr]P
215	Write the pattern space, up to the first newline character to the
216	standard output.
217
218	[1addr]q
219	Branch to the end of the script and quit without starting a new
220	cycle.
221
222	[1addr]r file
223	Copy the contents of _\bf_\bi_\bl_\be to the standard output immediately be-
224	fore the next attempt to read a line of input. If _\bf_\bi_\bl_\be cannot be
225	read for any reason, it is silently ignored and no error condi-
226	tion is set.
227
228	[2addr]s/regular expression/replacement/flags
229	Substitute the replacement string for the first instance of the
230	regular expression in the pattern space. Any character other
231	than backslash or newline can be used instead of a slash to de-
232	limit the RE and the replacement. Within the RE and the replace-
233	ment, the RE delimiter itself can be used as a literal character
234	if it is preceded by a backslash.
235
236	An ampersand (``&'') appearing in the replacement is replaced by
237	the string matching the RE. The special meaning of ``&'' in this
238	context can be suppressed by preceding it by backslash. The
239	string ``\#'', where ``#'' is a digit, is replaced by the text
240	matched by the corresponding backreference expression (see
241	re_format(7)).
242
243	A line can be split by substituting a newline character into it.
244	To specify a newline character in the replacement string, precede
245	it with a backslash.
246
247	The value of _\bf_\bl_\ba_\bg_\bs in the substitute function is zero or more of
248	the following:
249
250	0 ... 9
251	Make the substitution only for the N'th occurrence
252	of the regular expression in the pattern space.
253
254	g Make the substitution for all non-overlapping
255	matches of the regular expression, not just the
256	first one.
257
258	p Write the pattern space to standard output if a re-
259	placement was made. If the replacement string is
260	identical to that which it replaces, it is still
261	considered to have been a replacement.
262
263	w _\bf_\bi_\bl_\be Append the pattern space to _\bf_\bi_\bl_\be if a replacement
264	was made. If the replacement string is identical
265	to that which it replaces, it is still considered
266	to have been a replacement.
267
268	[2addr]t [label]
269	Branch to the ``'': function bearing the label if any substitu-
270	tions have been made since the most recent reading of an input
271	line or execution of a ``t'' function. If no label is specified,
272	branch to the end of the script.
273
274	[2addr]w _\bf_\bi_\bl_\be
275	Append the pattern space to the _\bf_\bi_\bl_\be.
276
277	[2addr]x
278	Swap the contents of the pattern and hold spaces.
279
280	[2addr]y/string1/string2/
281	Replace all occurrences of characters in _\bs_\bt_\br_\bi_\bn_\bg_\b1 in the pattern
282	space with the corresponding characters from _\bs_\bt_\br_\bi_\bn_\bg_\b2. Any charac-
283	ter other than a backslash or newline can be used instead of a
284	slash to delimit the strings. Within _\bs_\bt_\br_\bi_\bn_\bg_\b1 and _\bs_\bt_\br_\bi_\bn_\bg_\b2, a
285	backslash followed by any character other than a newline is that
286	literal character, and a backslash followed by an ``n'' is re-
287	placed by a newline character.
288
289	[2addr]!function
290	[2addr]!function-list
291	Apply the function or function-list only to the lines that are
292	_\bn_\bo_\bt selected by the address(es).
293
294	[0addr]:label
295	This function does nothing; it bears a label to which the ``b''
296	and ``t'' commands may branch.
297
298	[1addr]=
299	Write the line number to the standard output followed by a new-
300	line character.
301
302	[0addr]
303	Empty lines are ignored.
304
305	[0addr]#
306	The ``#'' and the remainder of the line are ignored (treated as a
307	comment), with the single exception that if the first two charac-
308	ters in the file are ``#n'', the default output is suppressed.
309	This is the same as specifying the -\b-n\bn option on the command line.
310
311	The s\bse\bed\bd utility exits 0 on success and >0 if an error occurs.
312
313	S\bSE\bEE\bE A\bAL\bLS\bSO\bO
314	awk(1), ed(1), grep(1), regex(3), re_format(7)
315
316	H\bHI\bIS\bST\bTO\bOR\bRY\bY
317	A s\bse\bed\bd command appeared in Version 7 AT&T UNIX.
318
319	S\bST\bTA\bAN\bND\bDA\bAR\bRD\bDS\bS
320	The s\bse\bed\bd function is expected to be a superset of the IEEE Std1003.2
321	(``POSIX'') specification.
322
323	4.4BSD June 6, 1993 5