tsed.1 - plan9port - [fork] Plan 9 from user space
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tsed.1 (6957B)
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1 .TH SED 1
2 .SH NAME
3 sed \- stream editor
4 .SH SYNOPSIS
5 .B sed
6 [
7 .B -gln
8 ]
9 [
10 .B -e
11 .I script
12 ]
13 [
14 .B -f
15 .I sfile
16 ]
17 [
18 .I file ...
19 ]
20 .SH DESCRIPTION
21 .I Sed
22 copies the named
23 .I files
24 (standard input default) to the standard output,
25 edited according to a script of commands.
26 The
27 .B -f
28 option causes the script to be taken from file
29 .IR sfile ;
30 these options accumulate.
31 If there is just one
32 .B -e
33 option and no
34 .BR -f 's,
35 the flag
36 .B -e
37 may be omitted.
38 The
39 .B -n
40 option suppresses the default output;
41 .B -g
42 causes all substitutions to be global, as if suffixed
43 .BR g .
44 The
45 .B -l
46 option causes
47 .I sed
48 to flush its output buffer after every newline.
49 .PP
50 A script consists of editing commands, one per line,
51 of the following form:
52 .IP
53 [\fIaddress\fR [\fL,\fI address\fR] ] \fIfunction\fR [\fIargument\fR ...]
54 .PP
55 In normal operation
56 .I sed
57 cyclically copies a line of input into a
58 .I pattern space
59 (unless there is something left after
60 a
61 .L D
62 command),
63 applies in sequence
64 all commands whose
65 .I addresses
66 select that pattern space,
67 and at the end of the script copies the pattern space
68 to the standard output (except under
69 .BR -n )
70 and deletes the pattern space.
71 .PP
72 An
73 .I address
74 is either a decimal number that counts
75 input lines cumulatively across files, a
76 .L $
77 that
78 addresses the last line of input, or a context address,
79 .BI / regular-expression / \f1,
80 in the style of
81 .MR regexp (7) ,
82 with the added convention that
83 .L \en
84 matches a
85 newline embedded in the pattern space.
86 .PP
87 A command line with no addresses selects every pattern space.
88 .PP
89 A command line with
90 one address selects each pattern space that matches the address.
91 .PP
92 A command line with
93 two addresses selects the inclusive range from the first
94 pattern space that matches the first address through
95 the next pattern space that matches
96 the second.
97 (If the second address is a number less than or equal
98 to the line number first selected, only one
99 line is selected.)
100 Thereafter the process is repeated, looking again for the
101 first address.
102 .PP
103 Editing commands can be applied to non-selected pattern
104 spaces by use of the negation function
105 .L !
106 (below).
107 .PP
108 An argument denoted
109 .I text
110 consists of one or more lines,
111 all but the last of which end with
112 .L \e
113 to hide the
114 newline.
115 Backslashes in text are treated like backslashes
116 in the replacement string of an
117 .L s
118 command,
119 and may be used to protect initial blanks and tabs
120 against the stripping that is done on
121 every script line.
122 .PP
123 An argument denoted
124 .I rfile
125 or
126 .I wfile
127 must terminate the command
128 line and must be preceded by exactly one blank.
129 Each
130 .I wfile
131 is created before processing begins.
132 There can be at most 120 distinct
133 .I wfile
134 arguments.
135 .TP \w'\fL!\ \fIfunction\fLXXX'u
136 .B a\e
137 .br
138 .ns
139 .TP
140 .I text
141 Append.
142 Place
143 .I text
144 on the output before
145 reading the next input line.
146 .TP
147 .BI b " label"
148 Branch to the
149 .B :
150 command bearing the
151 .IR label .
152 If
153 .I label
154 is empty, branch to the end of the script.
155 .TP
156 .B c\e
157 .br
158 .ns
159 .TP
160 .I text
161 Change.
162 Delete the pattern space.
163 With 0 or 1 address or at the end of a 2-address range, place
164 .I text
165 on the output.
166 Start the next cycle.
167 .TP
168 .B d
169 Delete the pattern space.
170 Start the next cycle.
171 .TP
172 .B D
173 Delete the initial segment of the
174 pattern space through the first newline.
175 Start the next cycle.
176 .TP
177 .B g
178 Replace the contents of the pattern space
179 by the contents of the hold space.
180 .TP
181 .B G
182 Append the contents of the hold space to the pattern space.
183 .TP
184 .B h
185 Replace the contents of the hold space by the contents of the pattern space.
186 .TP
187 .B H
188 Append the contents of the pattern space to the hold space.
189 .ne 3
190 .TP
191 .B i\e
192 .br
193 .ns
194 .TP
195 .I text
196 Insert.
197 Place
198 .I text
199 on the standard output.
200 .TP
201 .B n
202 Copy the pattern space to the standard output.
203 Replace the pattern space with the next line of input.
204 .TP
205 .B N
206 Append the next line of input to the pattern space
207 with an embedded newline.
208 (The current line number changes.)
209 .TP
210 .B p
211 Print.
212 Copy the pattern space to the standard output.
213 .TP
214 .B P
215 Copy the initial segment of the pattern space through
216 the first newline to the standard output.
217 .TP
218 .B q
219 Quit.
220 Branch to the end of the script.
221 Do not start a new cycle.
222 .TP
223 .BI r " rfile"
224 Read the contents of
225 .IR rfile .
226 Place them on the output before reading
227 the next input line.
228 .TP
229 .B s/\fIregular-expression\fP/\fIreplacement\fP/\fIflags
230 Substitute the
231 .I replacement
232 string for instances of the
233 .I regular-expression
234 in the pattern space.
235 Any character may be used instead of
236 .LR / .
237 For a fuller description see
238 .MR regexp (7) .
239 .I Flags
240 is zero or more of
241 .RS
242 .TP
243 .B g
244 Global.
245 Substitute for all non-overlapping instances of the
246 .I regular expression
247 rather than just the
248 first one.
249 .TP
250 .B p
251 Print the pattern space if a replacement was made.
252 .TP
253 .BI w " wfile"
254 Write.
255 Append the pattern space to
256 .I wfile
257 if a replacement
258 was made.
259 .RE
260 .TP
261 .BI t " label"
262 Test.
263 Branch to the
264 .L :
265 command bearing the
266 .I label
267 if any
268 substitutions have been made since the most recent
269 reading of an input line or execution of a
270 .LR t .
271 If
272 .I label
273 is empty, branch to the end of the script.
274 .TP
275 .B w
276 .I wfile
277 .br
278 Write.
279 Append the pattern space to
280 .IR wfile .
281 .TP
282 .B x
283 Exchange the contents of the pattern and hold spaces.
284 .TP
285 .B y/\fIstring1\fP/\fIstring2\fP/
286 Transform.
287 Replace all occurrences of characters in
288 .I string1
289 with the corresponding character in
290 .IR string2 .
291 The lengths of
292 .I
293 string1
294 and
295 .I string2
296 must be equal.
297 .TP
298 .BI ! "function"
299 Don't.
300 Apply the
301 .I function
302 (or group, if
303 .I function
304 is
305 .LR { )
306 only to lines
307 .I not
308 selected by the address(es).
309 .TP
310 .BI : " label"
311 This command does nothing; it bears a
312 .I label
313 for
314 .B b
315 and
316 .B t
317 commands to branch to.
318 .TP
319 .B =
320 Place the current line number on the standard output as a line.
321 .TP
322 .B {
323 Execute the following commands through a matching
324 .L }
325 only when the pattern space is selected.
326 .TP
327 .B " "
328 An empty command is ignored.
329 .ne 4
330 .SH EXAMPLES
331 .TP
332 .B sed 10q file
333 Print the first 10 lines of the file.
334 .TP
335 .B sed '/^$/d'
336 Delete empty lines from standard input.
337 .TP
338 .B sed 's/UNIX/& system/g'
339 Replace every instance of
340 .L UNIX
341 by
342 .LR "UNIX system" .
343 .PP
344 .EX
345 sed 's/ *$// \fRdrop trailing blanks\fP
346 /^$/d \fRdrop empty lines\fP
347 s/ */\e \fRreplace blanks by newlines\fP
348 /g
349 /^$/d' chapter*
350 .EE
351 .ns
352 .IP
353 Print the files
354 .BR chapter1 ,
355 .BR chapter2 ,
356 etc. one word to a line.
357 .PP
358 .EX
359 nroff -ms manuscript | sed '
360 ${
361 /^$/p \fRif last line of file is empty, print it\fP
362 }
363 //N \fRif current line is empty, append next line\fP
364 /^\en$/D' \fRif two lines are empty, delete the first\fP
365 .EE
366 .ns
367 .IP
368 Delete all but one of each group of empty lines from a
369 formatted manuscript.
370 .SH SOURCE
371 .B \*9/src/cmd/sed.c
372 .SH SEE ALSO
373 .IR ed (1),
374 .IR grep (1),
375 .IR awk (1),
376 .IR lex (1),
377 .MR sam (1) ,
378 .MR regexp (7)
379 .br
380 L. E. McMahon,
381 `SED \(em A Non-interactive Text Editor',
382 Unix Research System Programmer's Manual, Volume 2.
383 .SH BUGS
384 If input is from a pipe, buffering may consume
385 characters beyond a line on which a
386 .L q
387 command is executed.