xref: /freebsd/usr.bin/sed/sed.1 (revision 52ec752989b2e6d4e9a59a8ff25d8ff596d85e62)
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35.\"	@(#)sed.1	8.2 (Berkeley) 12/30/93
36.\" $FreeBSD$
37.\"
38.Dd May 7, 2002
39.Dt SED 1
40.Os
41.Sh NAME
42.Nm sed
43.Nd stream editor
44.Sh SYNOPSIS
45.Nm
46.Op Fl Ean
47.Ar command
48.Op Ar
49.Nm
50.Op Fl Ean
51.Op Fl e Ar command
52.Op Fl f Ar command_file
53.Op Fl i Ar extension
54.Op Ar
55.Sh DESCRIPTION
56The
57.Nm
58utility reads the specified files, or the standard input if no files
59are specified, modifying the input as specified by a list of commands.
60The input is then written to the standard output.
61.Pp
62A single command may be specified as the first argument to
63.Nm .
64Multiple commands may be specified by using the
65.Fl e
66or
67.Fl f
68options.
69All commands are applied to the input in the order they are specified
70regardless of their origin.
71.Pp
72The following options are available:
73.Bl -tag -width indent
74.It Fl E
75Interpret regular expressions as extended (modern) regular expressions
76rather than basic regular expressions (BRE's).
77The
78.Xr re_format 7
79manual page fully describes both formats.
80.It Fl a
81The files listed as parameters for the
82.Dq w
83functions are created (or truncated) before any processing begins,
84by default.
85The
86.Fl a
87option causes
88.Nm
89to delay opening each file until a command containing the related
90.Dq w
91function is applied to a line of input.
92.It Fl e Ar command
93Append the editing commands specified by the
94.Ar command
95argument
96to the list of commands.
97.It Fl f Ar command_file
98Append the editing commands found in the file
99.Ar command_file
100to the list of commands.
101The editing commands should each be listed on a separate line.
102.It Fl i Ar extension
103Edit files in-place, saving backups with the specified
104.Ar extension .
105If a zero-length
106.Ar extension
107is given, no backup will be saved.
108It is not recommended to give a zero-length
109.Ar extension
110when in-place editing files, as you risk corruption or partial content
111in situations where disk space is exhausted, etc.
112.It Fl n
113By default, each line of input is echoed to the standard output after
114all of the commands have been applied to it.
115The
116.Fl n
117option suppresses this behavior.
118.El
119.Pp
120The form of a
121.Nm
122command is as follows:
123.Pp
124.Dl [address[,address]]function[arguments]
125.Pp
126Whitespace may be inserted before the first address and the function
127portions of the command.
128.Pp
129Normally,
130.Nm
131cyclically copies a line of input, not including its terminating newline
132character, into a
133.Em "pattern space" ,
134(unless there is something left after a
135.Dq D
136function),
137applies all of the commands with addresses that select that pattern space,
138copies the pattern space to the standard output, appending a newline, and
139deletes the pattern space.
140.Pp
141Some of the functions use a
142.Em "hold space"
143to save all or part of the pattern space for subsequent retrieval.
144.Sh "Sed Addresses"
145An address is not required, but if specified must be a number (that counts
146input lines
147cumulatively across input files), a dollar
148.Pq Dq $
149character that addresses the last line of input, or a context address
150(which consists of a regular expression preceded and followed by a
151delimiter).
152.Pp
153A command line with no addresses selects every pattern space.
154.Pp
155A command line with one address selects all of the pattern spaces
156that match the address.
157.Pp
158A command line with two addresses selects an inclusive range.  This
159range starts with the first pattern space that matches the first
160address.  The end of the range is the next following pattern space
161that matches the second address.  If the second address is a number
162less than or equal to the line number first selected, only that
163line is selected.  In the case when the second address is a context
164address,
165.Nm
166does not re-match the second address against the
167pattern space that matched the first address.  Starting at the
168first line following the selected range,
169.Nm
170starts looking again for the first address.
171.Pp
172Editing commands can be applied to non-selected pattern spaces by use
173of the exclamation character
174.Pq Dq \&!
175function.
176.Sh "Sed Regular Expressions"
177The regular expressions used in
178.Nm ,
179by default, are basic regular expressions (BREs, see
180.Xr re_format 7
181for more information), but extended (modern) regular expressions can be used
182instead if the
183.Fl E
184flag is given.
185In addition,
186.Nm
187has the following two additions to regular expressions:
188.Pp
189.Bl -enum -compact
190.It
191In a context address, any character other than a backslash
192.Pq Dq \e
193or newline character may be used to delimit the regular expression.
194Also, putting a backslash character before the delimiting character
195causes the character to be treated literally.
196For example, in the context address \exabc\exdefx, the RE delimiter
197is an
198.Dq x
199and the second
200.Dq x
201stands for itself, so that the regular expression is
202.Dq abcxdef .
203.Pp
204.It
205The escape sequence \en matches a newline character embedded in the
206pattern space.
207You can't, however, use a literal newline character in an address or
208in the substitute command.
209.El
210.Pp
211One special feature of
212.Nm
213regular expressions is that they can default to the last regular
214expression used.
215If a regular expression is empty, i.e. just the delimiter characters
216are specified, the last regular expression encountered is used instead.
217The last regular expression is defined as the last regular expression
218used as part of an address or substitute command, and at run-time, not
219compile-time.
220For example, the command
221.Dq /abc/s//XXX/
222will substitute
223.Dq XXX
224for the pattern
225.Dq abc .
226.Sh "Sed Functions"
227In the following list of commands, the maximum number of permissible
228addresses for each command is indicated by [0addr], [1addr], or [2addr],
229representing zero, one, or two addresses.
230.Pp
231The argument
232.Em text
233consists of one or more lines.
234To embed a newline in the text, precede it with a backslash.
235Other backslashes in text are deleted and the following character
236taken literally.
237.Pp
238The
239.Dq r
240and
241.Dq w
242functions take an optional file parameter, which should be separated
243from the function letter by white space.
244Each file given as an argument to
245.Nm
246is created (or its contents truncated) before any input processing begins.
247.Pp
248The
249.Dq b ,
250.Dq r ,
251.Dq s ,
252.Dq t ,
253.Dq w ,
254.Dq y ,
255.Dq \&! ,
256and
257.Dq \&:
258functions all accept additional arguments.
259The following synopses indicate which arguments have to be separated from
260the function letters by white space characters.
261.Pp
262Two of the functions take a function-list.
263This is a list of
264.Nm
265functions separated by newlines, as follows:
266.Bd -literal -offset indent
267{ function
268  function
269  ...
270  function
271}
272.Ed
273.Pp
274The
275.Dq {
276can be preceded by white space and can be followed by white space.
277The function can be preceded by white space.
278The terminating
279.Dq }
280must be preceded by a newline or optional white space.
281.Pp
282.Bl -tag -width "XXXXXX" -compact
283.It [2addr] function-list
284Execute function-list only when the pattern space is selected.
285.Pp
286.It [1addr]a\e
287.It text
288Write
289.Em text
290to standard output immediately before each attempt to read a line of input,
291whether by executing the
292.Dq N
293function or by beginning a new cycle.
294.Pp
295.It [2addr]b[label]
296Branch to the
297.Dq \&:
298function with the specified label.
299If the label is not specified, branch to the end of the script.
300.Pp
301.It [2addr]c\e
302.It text
303Delete the pattern space.
304With 0 or 1 address or at the end of a 2-address range,
305.Em text
306is written to the standard output.
307.Pp
308.It [2addr]d
309Delete the pattern space and start the next cycle.
310.Pp
311.It [2addr]D
312Delete the initial segment of the pattern space through the first
313newline character and start the next cycle.
314.Pp
315.It [2addr]g
316Replace the contents of the pattern space with the contents of the
317hold space.
318.Pp
319.It [2addr]G
320Append a newline character followed by the contents of the hold space
321to the pattern space.
322.Pp
323.It [2addr]h
324Replace the contents of the hold space with the contents of the
325pattern space.
326.Pp
327.It [2addr]H
328Append a newline character followed by the contents of the pattern space
329to the hold space.
330.Pp
331.It [1addr]i\e
332.It text
333Write
334.Em text
335to the standard output.
336.Pp
337.It [2addr]l
338(The letter ell.)
339Write the pattern space to the standard output in a visually unambiguous
340form.
341This form is as follows:
342.Pp
343.Bl -tag -width "carriage-returnXX" -offset indent -compact
344.It backslash
345\e\e
346.It alert
347\ea
348.It form-feed
349\ef
350.It carriage-return
351\er
352.It tab
353\et
354.It vertical tab
355\ev
356.El
357.Pp
358Nonprintable characters are written as three-digit octal numbers (with a
359preceding backslash) for each byte in the character (most significant byte
360first).
361Long lines are folded, with the point of folding indicated by displaying
362a backslash followed by a newline.
363The end of each line is marked with a
364.Dq $ .
365.Pp
366.It [2addr]n
367Write the pattern space to the standard output if the default output has
368not been suppressed, and replace the pattern space with the next line of
369input.
370.Pp
371.It [2addr]N
372Append the next line of input to the pattern space, using an embedded
373newline character to separate the appended material from the original
374contents.
375Note that the current line number changes.
376.Pp
377.It [2addr]p
378Write the pattern space to standard output.
379.Pp
380.It [2addr]P
381Write the pattern space, up to the first newline character to the
382standard output.
383.Pp
384.It [1addr]q
385Branch to the end of the script and quit without starting a new cycle.
386.Pp
387.It [1addr]r file
388Copy the contents of
389.Em file
390to the standard output immediately before the next attempt to read a
391line of input.
392If
393.Em file
394cannot be read for any reason, it is silently ignored and no error
395condition is set.
396.Pp
397.It [2addr]s/regular expression/replacement/flags
398Substitute the replacement string for the first instance of the regular
399expression in the pattern space.
400Any character other than backslash or newline can be used instead of
401a slash to delimit the RE and the replacement.
402Within the RE and the replacement, the RE delimiter itself can be used as
403a literal character if it is preceded by a backslash.
404.Pp
405An ampersand
406.Pq Dq &
407appearing in the replacement is replaced by the string matching the RE.
408The special meaning of
409.Dq &
410in this context can be suppressed by preceding it by a backslash.
411The string
412.Dq \e# ,
413where
414.Dq #
415is a digit, is replaced by the text matched
416by the corresponding backreference expression (see
417.Xr re_format 7 ) .
418.Pp
419A line can be split by substituting a newline character into it.
420To specify a newline character in the replacement string, precede it with
421a backslash.
422.Pp
423The value of
424.Em flags
425in the substitute function is zero or more of the following:
426.Bl -tag -width "XXXXXX" -offset indent
427.It Ar N
428Make the substitution only for the
429.Ar N Ns 'th
430occurrence of the regular expression in the pattern space.
431.It g
432Make the substitution for all non-overlapping matches of the
433regular expression, not just the first one.
434.It p
435Write the pattern space to standard output if a replacement was made.
436If the replacement string is identical to that which it replaces, it
437is still considered to have been a replacement.
438.It w Em file
439Append the pattern space to
440.Em file
441if a replacement was made.
442If the replacement string is identical to that which it replaces, it
443is still considered to have been a replacement.
444.El
445.Pp
446.It [2addr]t [label]
447Branch to the
448.Dq \&:
449function bearing the label if any substitutions have been made since the
450most recent reading of an input line or execution of a
451.Dq t
452function.
453If no label is specified, branch to the end of the script.
454.Pp
455.It [2addr]w Em file
456Append the pattern space to the
457.Em file .
458.Pp
459.It [2addr]x
460Swap the contents of the pattern and hold spaces.
461.Pp
462.It [2addr]y/string1/string2/
463Replace all occurrences of characters in
464.Em string1
465in the pattern space with the corresponding characters from
466.Em string2 .
467Any character other than a backslash or newline can be used instead of
468a slash to delimit the strings.
469Within
470.Em string1
471and
472.Em string2 ,
473a backslash followed by any character other than a newline is that literal
474character, and a backslash followed by an ``n'' is replaced by a newline
475character.
476.Pp
477.It [2addr]!function
478.It [2addr]!function-list
479Apply the function or function-list only to the lines that are
480.Em not
481selected by the address(es).
482.Pp
483.It [0addr]:label
484This function does nothing; it bears a label to which the
485.Dq b
486and
487.Dq t
488commands may branch.
489.Pp
490.It [1addr]=
491Write the line number to the standard output followed by a newline
492character.
493.Pp
494.It [0addr]
495Empty lines are ignored.
496.Pp
497.It [0addr]#
498The
499.Dq #
500and the remainder of the line are ignored (treated as a comment), with
501the single exception that if the first two characters in the file are
502.Dq #n ,
503the default output is suppressed.
504This is the same as specifying the
505.Fl n
506option on the command line.
507.El
508.Sh ENVIRONMENT
509The
510.Ev COLUMNS , LANG , LC_ALL , LC_CTYPE
511and
512.Ev LC_COLLATE
513environment variables affect the execution of
514.Nm
515as described in
516.Xr environ 7 .
517.Sh DIAGNOSTICS
518.Ex -std
519.Sh SEE ALSO
520.Xr awk 1 ,
521.Xr ed 1 ,
522.Xr grep 1 ,
523.Xr regex 3 ,
524.Xr re_format 7
525.Sh STANDARDS
526The
527.Nm
528utility is expected to be a superset of the
529.St -p1003.2
530specification.
531.Pp
532The
533.Fl i
534option is a non-standard
535.Fx
536extension and may not be available on other operating systems.
537.Sh HISTORY
538A
539.Nm
540command, written by L. E. McMahon, appeared in
541.At v7 .
542.Sh AUTHORS
543.An "Diomidis D. Spinellis" Aq dds@FreeBSD.org
544