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47 .Op Fl f Ar command_file
54 utility reads the specified files, or the standard input if no files
55 are specified, modifying the input as specified by a list of commands.
56 The input is then written to the standard output.
58 A single command may be specified as the first argument to
60 Multiple commands may be specified by using the
65 All commands are applied to the input in the order they are specified
66 regardless of their origin.
68 The following options are available:
69 .Bl -tag -width indent
71 Interpret regular expressions as extended (modern) regular expressions
72 rather than basic regular expressions (BRE's).
75 manual page fully describes both formats.
77 The files listed as parameters for the
79 functions are created (or truncated) before any processing begins,
85 to delay opening each file until a command containing the related
87 function is applied to a line of input.
89 Append the editing commands specified by the
92 to the list of commands.
93 .It Fl f Ar command_file
94 Append the editing commands found in the file
96 to the list of commands.
97 The editing commands should each be listed on a separate line.
98 The commands are read from the standard input if
102 .It Fl I Ar extension
103 Edit files in-place, saving backups with the specified
107 is given, no backup will be saved.
108 It is not recommended to give a zero-length
110 when in-place editing files, as you risk corruption or partial content
111 in situations where disk space is exhausted, etc.
113 Note that in-place editing with
115 still takes place in a single continuous line address space covering
116 all files, although each file preserves its individuality instead of
117 forming one output stream.
118 The line counter is never reset between files, address ranges can span
119 file boundaries, and the
121 address matches only the last line of the last file.
123 .Sx "Sed Addresses" . )
124 That can lead to unexpected results in many cases of in-place editing,
128 .It Fl i Ar extension
129 Edit files in-place similarly to
131 but treat each file independently from other files.
132 In particular, line numbers in each file start at 1,
135 address matches the last line of the current file,
136 and address ranges are limited to the current file.
138 .Sx "Sed Addresses" . )
139 The net result is as though each file were edited by a separate
143 Make output line buffered.
145 By default, each line of input is echoed to the standard output after
146 all of the commands have been applied to it.
149 option suppresses this behavior.
153 for compatibility with GNU sed.
155 Make output unbuffered.
160 command is as follows:
162 .Dl [address[,address]]function[arguments]
164 Whitespace may be inserted before the first address and the function
165 portions of the command.
169 cyclically copies a line of input, not including its terminating newline
171 .Em "pattern space" ,
172 (unless there is something left after a
175 applies all of the commands with addresses that select that pattern space,
176 copies the pattern space to the standard output, appending a newline, and
177 deletes the pattern space.
179 Some of the functions use a
181 to save all or part of the pattern space for subsequent retrieval.
183 An address is not required, but if specified must have one of the
185 .Bl -bullet -offset indent
189 cumulatively across input files (or in each file independently
192 option is in effect);
196 character that addresses the last line of input (or the last line
197 of the current file if a
199 option was specified);
202 that consists of a regular expression preceded and followed by a
204 The closing delimiter can also optionally be followed by the
206 character, to indicate that the regular expression is to be matched
207 in a case-insensitive way.
210 A command line with no addresses selects every pattern space.
212 A command line with one address selects all of the pattern spaces
213 that match the address.
215 A command line with two addresses selects an inclusive range.
217 range starts with the first pattern space that matches the first
219 The end of the range is the next following pattern space
220 that matches the second address.
221 If the second address is a number
222 less than or equal to the line number first selected, only that
224 The number in the second address may be prefixed with a
226 to specify the number of lines to match after the first pattern.
227 In the case when the second address is a context
230 does not re-match the second address against the
231 pattern space that matched the first address.
233 first line following the selected range,
235 starts looking again for the first address.
237 Editing commands can be applied to non-selected pattern spaces by use
238 of the exclamation character
241 .Sh "Sed Regular Expressions"
242 The regular expressions used in
244 by default, are basic regular expressions (BREs, see
246 for more information), but extended (modern) regular expressions can be used
252 has the following two additions to regular expressions:
256 In a context address, any character other than a backslash
258 or newline character may be used to delimit the regular expression.
259 The opening delimiter needs to be preceded by a backslash
260 unless it is a slash.
261 For example, the context address
265 Also, putting a backslash character before the delimiting character
266 within the regular expression causes the character to be treated literally.
267 For example, in the context address
269 the RE delimiter is an
273 stands for itself, so that the regular expression is
277 The escape sequence \en matches a newline character embedded in the
279 You cannot, however, use a literal newline character in an address or
280 in the substitute command.
283 One special feature of
285 regular expressions is that they can default to the last regular
287 If a regular expression is empty, i.e., just the delimiter characters
288 are specified, the last regular expression encountered is used instead.
289 The last regular expression is defined as the last regular expression
290 used as part of an address or substitute command, and at run-time, not
292 For example, the command
299 In the following list of commands, the maximum number of permissible
300 addresses for each command is indicated by [0addr], [1addr], or [2addr],
301 representing zero, one, or two addresses.
305 consists of one or more lines.
306 To embed a newline in the text, precede it with a backslash.
307 Other backslashes in text are deleted and the following character
314 functions take an optional file parameter, which should be separated
315 from the function letter by white space.
316 Each file given as an argument to
318 is created (or its contents truncated) before any input processing begins.
330 functions all accept additional arguments.
331 The following synopses indicate which arguments have to be separated from
332 the function letters by white space characters.
334 Two of the functions take a function-list.
337 functions separated by newlines, as follows:
338 .Bd -literal -offset indent
348 can be preceded by white space and can be followed by white space.
349 The function can be preceded by white space.
352 must be preceded by a newline, and may also be preceded by white space.
354 .Bl -tag -width "XXXXXX" -compact
355 .It [2addr] function-list
356 Execute function-list only when the pattern space is selected.
362 to standard output immediately before each attempt to read a line of input,
363 whether by executing the
365 function or by beginning a new cycle.
370 function with the specified label.
371 If the label is not specified, branch to the end of the script.
375 Delete the pattern space.
376 With 0 or 1 address or at the end of a 2-address range,
378 is written to the standard output.
381 Delete the pattern space and start the next cycle.
384 Delete the initial segment of the pattern space through the first
385 newline character and start the next cycle.
388 Replace the contents of the pattern space with the contents of the
392 Append a newline character followed by the contents of the hold space
393 to the pattern space.
396 Replace the contents of the hold space with the contents of the
400 Append a newline character followed by the contents of the pattern space
407 to the standard output.
411 Write the pattern space to the standard output in a visually unambiguous
413 This form is as follows:
415 .Bl -tag -width "carriage-returnXX" -offset indent -compact
430 Nonprintable characters are written as three-digit octal numbers (with a
431 preceding backslash) for each byte in the character (most significant byte
433 Long lines are folded, with the point of folding indicated by displaying
434 a backslash followed by a newline.
435 The end of each line is marked with a
439 Write the pattern space to the standard output if the default output has
440 not been suppressed, and replace the pattern space with the next line of
444 Append the next line of input to the pattern space, using an embedded
445 newline character to separate the appended material from the original
447 Note that the current line number changes.
450 Write the pattern space to standard output.
453 Write the pattern space, up to the first newline character to the
457 Branch to the end of the script and quit without starting a new cycle.
462 to the standard output immediately before the next attempt to read a
466 cannot be read for any reason, it is silently ignored and no error
469 .It [2addr]s/regular expression/replacement/flags
470 Substitute the replacement string for the first instance of the regular
471 expression in the pattern space.
472 Any character other than backslash or newline can be used instead of
473 a slash to delimit the RE and the replacement.
474 Within the RE and the replacement, the RE delimiter itself can be used as
475 a literal character if it is preceded by a backslash.
479 appearing in the replacement is replaced by the string matching the RE.
480 The special meaning of
482 in this context can be suppressed by preceding it by a backslash.
487 is a digit, is replaced by the text matched
488 by the corresponding backreference expression (see
491 A line can be split by substituting a newline character into it.
492 To specify a newline character in the replacement string, precede it with
497 in the substitute function is zero or more of the following:
498 .Bl -tag -width "XXXXXX" -offset indent
500 Make the substitution only for the
502 occurrence of the regular expression in the pattern space.
504 Make the substitution for all non-overlapping matches of the
505 regular expression, not just the first one.
507 Write the pattern space to standard output if a replacement was made.
508 If the replacement string is identical to that which it replaces, it
509 is still considered to have been a replacement.
511 Append the pattern space to
513 if a replacement was made.
514 If the replacement string is identical to that which it replaces, it
515 is still considered to have been a replacement.
517 Match the regular expression in a case-insensitive way.
523 function bearing the label if any substitutions have been made since the
524 most recent reading of an input line or execution of a
527 If no label is specified, branch to the end of the script.
530 Append the pattern space to the
534 Swap the contents of the pattern and hold spaces.
536 .It [2addr]y/string1/string2/
537 Replace all occurrences of characters in
539 in the pattern space with the corresponding characters from
541 Any character other than a backslash or newline can be used instead of
542 a slash to delimit the strings.
547 a backslash followed by any character other than a newline is that literal
548 character, and a backslash followed by an ``n'' is replaced by a newline
552 .It [2addr]!function-list
553 Apply the function or function-list only to the lines that are
555 selected by the address(es).
558 This function does nothing; it bears a label to which the
565 Write the line number to the standard output followed by a newline
569 Empty lines are ignored.
574 and the remainder of the line are ignored (treated as a comment), with
575 the single exception that if the first two characters in the file are
577 the default output is suppressed.
578 This is the same as specifying the
580 option on the command line.
584 .Ev COLUMNS , LANG , LC_ALL , LC_CTYPE
587 environment variables affect the execution of
598 when piped from another command:
599 .Bd -literal -offset indent
600 echo "An alternate word, like bar, is sometimes used in examples." | sed 's/bar/baz/'
603 Using backlashes can sometimes be hard to read and follow:
604 .Bd -literal -offset indent
605 echo "/home/example" | sed 's/\\/home\\/example/\\/usr\\/local\\/example/'
608 Using a different separator can be handy when working with paths:
609 .Bd -literal -offset indent
610 echo "/home/example" | sed 's#/home/example#/usr/local/example#'
613 Replace all occurrences of
619 without creating a backup of the file:
620 .Bd -literal -offset indent
621 sed -i '' -e 's/foo/bar/g' test.txt
632 .%I AT&T Bell Laboratories
633 .%T SED \(em A Non-interactive Text Editor
634 .%R Computing Science Technical Report
641 utility is expected to be a superset of the
649 options, the special meaning of
653 in the second member of an address range,
656 flag to the address regular expression and substitution command are
659 extensions and may not be available on other operating systems.
668 .An Diomidis D. Spinellis Aq Mt dds@FreeBSD.org
670 Multibyte characters containing a byte with value 0x5C
673 may be incorrectly treated as line continuation characters in arguments to the
679 Multibyte characters cannot be used as delimiters with the