1ED(1P) POSIX Programmer's Manual ED(1P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 ed - edit text
13
15 ed [-p string][-s][file]
16
18 The ed utility is a line-oriented text editor that uses two modes: com‐
19 mand mode and input mode. In command mode the input characters shall be
20 interpreted as commands, and in input mode they shall be interpreted as
21 text. See the EXTENDED DESCRIPTION section.
22
24 The ed utility shall conform to the Base Definitions volume of
25 IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
26 The following options shall be supported:
28 -p string
30 Use string as the prompt string when in command mode. By
31 default, there shall be no prompt string.
32 -s Suppress the writing of byte counts by e, E, r, and w commands
34 and of the '!' prompt after a !command.
35
38 The following operand shall be supported:
39 file If the file argument is given, ed shall simulate an e command on
41 the file named by the pathname, file, before accepting commands
42 from the standard input. If the file operand is '-', the results
43 are unspecified.
44
47 The standard input shall be a text file consisting of commands, as
48 described in the EXTENDED DESCRIPTION section.
49
51 The input files shall be text files.
52
54 The following environment variables shall affect the execution of ed:
55 HOME Determine the pathname of the user's home directory.
57 LANG Provide a default value for the internationalization variables
59 that are unset or null. (See the Base Definitions volume of
60 IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
61 ables for the precedence of internationalization variables used
62 to determine the values of locale categories.)
63 LC_ALL If set to a non-empty string value, override the values of all
65 the other internationalization variables.
66 LC_COLLATE
68 Determine the locale for the behavior of ranges, equivalence
70 classes, and multi-character collating elements within regular
71 expressions.
72 LC_CTYPE
74 Determine the locale for the interpretation of sequences of
75 bytes of text data as characters (for example, single-byte as
76 opposed to multi-byte characters in arguments and input files)
77 and the behavior of character classes within regular expres‐
78 sions.
79 LC_MESSAGES
81 Determine the locale that should be used to affect the format
82 and contents of diagnostic messages written to standard error
83 and informative messages written to standard output.
84 NLSPATH
86 Determine the location of message catalogs for the processing of
87 LC_MESSAGES .
88
91 The ed utility shall take the standard action for all signals (see the
92 ASYNCHRONOUS EVENTS section in Utility Description Defaults ) with the
93 following exceptions:
94 SIGINT The ed utility shall interrupt its current activity, write the
96 string "?\n" to standard output, and return to command mode (see
97 the EXTENDED DESCRIPTION section).
98 SIGHUP If the buffer is not empty and has changed since the last write,
100 the ed utility shall attempt to write a copy of the buffer in a
101 file. First, the file named ed.hup in the current directory
102 shall be used; if that fails, the file named ed.hup in the
103 directory named by the HOME environment variable shall be used.
104 In any case, the ed utility shall exit without returning to com‐
105 mand mode.
106 SIGQUIT
108 The ed utility shall ignore this event.
109
112 Various editing commands and the prompting feature (see -p) write to
113 standard output, as described in the EXTENDED DESCRIPTION section.
114
116 The standard error shall be used only for diagnostic messages.
117
119 The output files shall be text files whose formats are dependent on the
120 editing commands given.
121
123 The ed utility shall operate on a copy of the file it is editing;
124 changes made to the copy shall have no effect on the file until a w
125 (write) command is given. The copy of the text is called the buffer.
126 Commands to ed have a simple and regular structure: zero, one, or two
128 addresses followed by a single-character command, possibly followed by
129 parameters to that command. These addresses specify one or more lines
130 in the buffer. Every command that requires addresses has default
131 addresses, so that the addresses very often can be omitted. If the -p
132 option is specified, the prompt string shall be written to standard
133 output before each command is read.
134 In general, only one command can appear on a line. Certain commands
136 allow text to be input. This text is placed in the appropriate place in
137 the buffer. While ed is accepting text, it is said to be in input mode.
138 In this mode, no commands shall be recognized; all input is merely col‐
139 lected. Input mode is terminated by entering a line consisting of two
140 characters: a period ( '.' ) followed by a <newline>. This line is not
141 considered part of the input text.
142 Regular Expressions in ed
144 The ed utility shall support basic regular expressions, as described in
145 the Base Definitions volume of IEEE Std 1003.1-2001, Section 9.3, Basic
146 Regular Expressions. Since regular expressions in ed are always matched
147 against single lines (excluding the terminating <newline>s), never
148 against any larger section of text, there is no way for a regular
149 expression to match a <newline>.
150 A null RE shall be equivalent to the last RE encountered.
152 Regular expressions are used in addresses to specify lines, and in some
154 commands (for example, the s substitute command) to specify portions of
155 a line to be substituted.
156 Addresses in ed
158 Addressing in ed relates to the current line. Generally, the current
159 line is the last line affected by a command. The current line number is
160 the address of the current line. If the edit buffer is not empty, the
161 initial value for the current line shall be the last line in the edit
162 buffer; otherwise, zero.
163 Addresses shall be constructed as follows:
165 1. The period character ( '.' ) shall address the current line.
167 2. The dollar sign character ( '$' ) shall address the last line of
169 the edit buffer.
170 3. The positive decimal number n shall address the nth line of the
172 edit buffer.
173 4. The apostrophe-x character pair ( "'x" ) shall address the line
175 marked with the mark name character x, which shall be a lowercase
176 letter from the portable character set. It shall be an error if the
177 character has not been set to mark a line or if the line that was
178 marked is not currently present in the edit buffer.
179 5. A BRE enclosed by slash characters ( '/' ) shall address the first
181 line found by searching forwards from the line following the cur‐
182 rent line toward the end of the edit buffer and stopping at the
183 first line for which the line excluding the terminating <newline>
184 matches the BRE. The BRE consisting of a null BRE delimited by a
185 pair of slash characters shall address the next line for which the
186 line excluding the terminating <newline> matches the last BRE
187 encountered. In addition, the second slash can be omitted at the
188 end of a command line. Within the BRE, a backslash-slash pair (
189 "\/" ) shall represent a literal slash instead of the BRE delim‐
190 iter. If necessary, the search shall wrap around to the beginning
191 of the buffer and continue up to and including the current line, so
192 that the entire buffer is searched.
193 6. A BRE enclosed by question-mark characters ( '?' ) shall address
195 the first line found by searching backwards from the line preceding
196 the current line toward the beginning of the edit buffer and stop‐
197 ping at the first line for which the line excluding the terminating
198 <newline> matches the BRE. The BRE consisting of a null BRE delim‐
199 ited by a pair of question-mark characters ( "??" ) shall address
200 the previous line for which the line excluding the terminating
201 <newline> matches the last BRE encountered. In addition, the second
202 question-mark can be omitted at the end of a command line. Within
203 the BRE, a backslash-question-mark pair ( "\?" ) shall represent a
204 literal question mark instead of the BRE delimiter. If necessary,
205 the search shall wrap around to the end of the buffer and continue
206 up to and including the current line, so that the entire buffer is
207 searched.
208 7. A plus-sign ( '+' ) or hyphen character ( '-' ) followed by a deci‐
210 mal number shall address the current line plus or minus the number.
211 A plus-sign or hyphen character not followed by a decimal number
212 shall address the current line plus or minus 1.
213 Addresses can be followed by zero or more address offsets, optionally
215 <blank>-separated. Address offsets are constructed as follows:
216 * A plus-sign or hyphen character followed by a decimal number shall
218 add or subtract, respectively, the indicated number of lines to or
219 from the address. A plus-sign or hyphen character not followed by a
220 decimal number shall add or subtract 1 to or from the address.
221 * A decimal number shall add the indicated number of lines to the
223 address.
224 It shall not be an error for an intermediate address value to be less
226 than zero or greater than the last line in the edit buffer. It shall be
227 an error for the final address value to be less than zero or greater
228 than the last line in the edit buffer. It shall be an error if a search
229 for a BRE fails to find a matching line.
230 Commands accept zero, one, or two addresses. If more than the required
232 number of addresses are provided to a command that requires zero
233 addresses, it shall be an error. Otherwise, if more than the required
234 number of addresses are provided to a command, the addresses specified
235 first shall be evaluated and then discarded until the maximum number of
236 valid addresses remain, for the specified command.
237 Addresses shall be separated from each other by a comma ( ',' ) or
239 semicolon character ( ';' ). In the case of a semicolon separator, the
240 current line ( '.' ) shall be set to the first address, and only then
241 will the second address be calculated. This feature can be used to
242 determine the starting line for forwards and backwards searches; see
243 rules 5. and 6.
244 Addresses can be omitted on either side of the comma or semicolon sepa‐
246 rator, in which case the resulting address pairs shall be as follows:
247 Specified Resulting
249 , 1 , $,
250 addr 1 , addr
251 addr , addr , addr
252 ; . ; $
253 ; addr . ; addr
254 addr ; addr ; addr
255 Any <blank>s included between addresses, address separators, or address
257 offsets shall be ignored.
258 Commands in ed
260 In the following list of ed commands, the default addresses are shown
261 in parentheses. The number of addresses shown in the default shall be
262 the number expected by the command. The parentheses are not part of the
263 address; they show that the given addresses are the default.
264 It is generally invalid for more than one command to appear on a line.
266 However, any command (except e, E, f, q, Q, r, w, and !) can be suf‐
267 fixed by the letter l, n, or p; in which case, except for the l, n, and
268 p commands, the command shall be executed and then the new current line
269 shall be written as described below under the l, n, and p commands.
270 When an l, n, or p suffix is used with an l, n, or p command, the com‐
271 mand shall write to standard output as described below, but it is
272 unspecified whether the suffix writes the current line again in the
273 requested format or whether the suffix has no effect. For example, the
274 pl command (base p command with an l suffix) shall either write just
275 the current line or write it twice-once as specified for p and once as
276 specified for l. Also, the g, G, v, and V commands shall take a com‐
277 mand as a parameter.
278 Each address component can be preceded by zero or more <blank>s. The
280 command letter can be preceded by zero or more <blank>s. If a suffix
281 letter ( l, n, or p) is given, the application shall ensure that it
282 immediately follows the command.
283 The e, E, f, r, and w commands shall take an optional file parameter,
285 separated from the command letter by one or more <blank>s.
286 If changes have been made in the buffer since the last w command that
288 wrote the entire buffer, ed shall warn the user if an attempt is made
289 to destroy the editor buffer via the e or q commands. The ed utility
290 shall write the string:
291 "?\n"
294 (followed by an explanatory message if help mode has been enabled via
296 the H command) to standard output and shall continue in command mode
297 with the current line number unchanged. If the e or q command is
298 repeated with no intervening command, it shall take effect.
299 If a terminal disconnect is detected:
301 * If the buffer is not empty and has changed since the last write, the
303 ed utility shall attempt to write a copy of the buffer to a file
304 named ed.hup in the current directory. If this write fails, ed shall
305 attempt to write a copy of the buffer to a filename ed.hup in the
306 directory named by the HOME environment variable. If both these
307 attempts fail, ed shall exit without saving the buffer.
308 * The ed utility shall not write the file to the currently remembered
310 pathname or return to command mode, and shall terminate with a non-
311 zero exit status.
312 If an end-of-file is detected on standard input:
314 * If the ed utility is in input mode, ed shall terminate input mode
316 and return to command mode. It is unspecified if any partially
317 entered lines (that is, input text without a terminating <newline>)
318 are discarded from the input text.
319 * If the ed utility is in command mode, it shall act as if a q command
321 had been entered.
322 If the closing delimiter of an RE or of a replacement string (for exam‐
324 ple, '/' ) in a g, G, s, v, or V command would be the last character
325 before a <newline>, that delimiter can be omitted, in which case the
326 addressed line shall be written. For example, the following pairs of
327 commands are equivalent:
328 s/s1/s2 s/s1/s2/p
331 g/s1 g/s1/p
332 ?s1 ?s1?
333 If an invalid command is entered, ed shall write the string:
335 "?\n"
338 (followed by an explanatory message if help mode has been enabled via
340 the H command) to standard output and shall continue in command mode
341 with the current line number unchanged.
342 Append Command
344 Synopsis:
345 (.)a
348 <text>
349 .
350 The a command shall read the given text and append it after the
353 addressed line; the current line number shall become the address of the
354 last inserted line or, if there were none, the addressed line. Address
355 0 shall be valid for this command; it shall cause the appended text to
356 be placed at the beginning of the buffer.
357 Change Command
359 Synopsis:
360 (.,.)c
363 <text>
364 .
365 The c command shall delete the addressed lines, then accept input text
368 that replaces these lines; the current line shall be set to the address
369 of the last line input; or, if there were none, at the line after the
370 last line deleted; if the lines deleted were originally at the end of
371 the buffer, the current line number shall be set to the address of the
372 new last line; if no lines remain in the buffer, the current line num‐
373 ber shall be set to zero. Address 0 shall be valid for this command;
374 it shall be interpreted as if address 1 were specified.
375 Delete Command
377 Synopsis:
378 (.,.)d
381 The d command shall delete the addressed lines from the buffer. The
384 address of the line after the last line deleted shall become the cur‐
385 rent line number; if the lines deleted were originally at the end of
386 the buffer, the current line number shall be set to the address of the
387 new last line; if no lines remain in the buffer, the current line num‐
388 ber shall be set to zero.
389 Edit Command
391 Synopsis:
392 e [file]
395 The e command shall delete the entire contents of the buffer and then
398 read in the file named by the pathname file. The current line number
399 shall be set to the address of the last line of the buffer. If no path‐
400 name is given, the currently remembered pathname, if any, shall be used
401 (see the f command). The number of bytes read shall be written to
402 standard output, unless the -s option was specified, in the following
403 format:
404 "%d\n", <number of bytes read>
407 The name file shall be remembered for possible use as a default path‐
409 name in subsequent e, E, r, and w commands. If file is replaced by '!',
410 the rest of the line shall be taken to be a shell command line whose
411 output is to be read. Such a shell command line shall not be remembered
412 as the current file. All marks shall be discarded upon the completion
413 of a successful e command. If the buffer has changed since the last
414 time the entire buffer was written, the user shall be warned, as
415 described previously.
416 Edit Without Checking Command
418 Synopsis:
419 E [file]
422 The E command shall possess all properties and restrictions of the e
425 command except that the editor shall not check to see whether any
426 changes have been made to the buffer since the last w command.
427 Filename Command
429 Synopsis:
430 f [file]
433 If file is given, the f command shall change the currently remembered
436 pathname to file; whether the name is changed or not, it shall then
437 write the (possibly new) currently remembered pathname to the standard
438 output in the following format:
439 "%s\n", <pathname>
442 The current line number shall be unchanged.
444 Global Command
446 Synopsis:
447 (1,$)g/RE/command list
450 In the g command, the first step shall be to mark every line for which
453 the line excluding the terminating <newline> matches the given RE.
454 Then, going sequentially from the beginning of the file to the end of
455 the file, the given command list shall be executed for each marked
456 line, with the current line number set to the address of that line. Any
457 line modified by the command list shall be unmarked. When the g command
458 completes, the current line number shall have the value assigned by the
459 last command in the command list. If there were no matching lines, the
460 current line number shall not be changed. A single command or the first
461 of a list of commands shall appear on the same line as the global com‐
462 mand. All lines of a multi-line list except the last line shall be
463 ended with a backslash preceding the terminating <newline>; the a, i,
464 and c commands and associated input are permitted. The '.' terminating
465 input mode can be omitted if it would be the last line of the command
466 list. An empty command list shall be equivalent to the p command. The
467 use of the g, G, v, V, and ! commands in the command list produces
468 undefined results. Any character other than <space> or <newline> can be
469 used instead of a slash to delimit the RE. Within the RE, the RE delim‐
470 iter itself can be used as a literal character if it is preceded by a
471 backslash.
472 Interactive Global Command
474 Synopsis:
475 (1,$)G/RE/
478 In the G command, the first step shall be to mark every line for which
481 the line excluding the terminating <newline> matches the given RE.
482 Then, for every such line, that line shall be written, the current line
483 number shall be set to the address of that line, and any one command
484 (other than one of the a, c, i, g, G, v, and V commands) shall be read
485 and executed. A <newline> shall act as a null command (causing no
486 action to be taken on the current line); an '&' shall cause the re-exe‐
487 cution of the most recent non-null command executed within the current
488 invocation of G. Note that the commands input as part of the execution
489 of the G command can address and affect any lines in the buffer. Any
490 line modified by the command shall be unmarked. The final value of the
491 current line number shall be the value set by the last command success‐
492 fully executed. (Note that the last command successfully executed shall
493 be the G command itself if a command fails or the null command is spec‐
494 ified.) If there were no matching lines, the current line number shall
495 not be changed. The G command can be terminated by a SIGINT signal. Any
496 character other than <space> or <newline> can be used instead of a
497 slash to delimit the RE and the replacement. Within the RE, the RE
498 delimiter itself can be used as a literal character if it is preceded
499 by a backslash.
500 Help Command
502 Synopsis:
503 h
506 The h command shall write a short message to standard output that
509 explains the reason for the most recent '?' notification. The current
510 line number shall be unchanged.
511 Help-Mode Command
513 Synopsis:
514 H
517 The H command shall cause ed to enter a mode in which help messages
520 (see the h command) shall be written to standard output for all subse‐
521 quent '?' notifications. The H command alternately shall turn this mode
522 on and off; it is initially off. If the help-mode is being turned on,
523 the H command also explains the previous '?' notification, if there was
524 one. The current line number shall be unchanged.
525 Insert Command
527 Synopsis:
528 (.)i
531 <text>
532 .
533 The i command shall insert the given text before the addressed line;
536 the current line is set to the last inserted line or, if there was
537 none, to the addressed line. This command differs from the a command
538 only in the placement of the input text. Address 0 shall be valid for
539 this command; it shall be interpreted as if address 1 were specified.
540 Join Command
542 Synopsis:
543 (.,.+1)j
546 The j command shall join contiguous lines by removing the appropriate
549 <newline>s. If exactly one address is given, this command shall do
550 nothing. If lines are joined, the current line number shall be set to
551 the address of the joined line; otherwise, the current line number
552 shall be unchanged.
553 Mark Command
555 Synopsis:
556 (.)kx
559 The k command shall mark the addressed line with name x, which the
562 application shall ensure is a lowercase letter from the portable char‐
563 acter set. The address "'x" shall then refer to this line; the current
564 line number shall be unchanged.
565 List Command
567 Synopsis:
568 (.,.)l
571 The l command shall write to standard output the addressed lines in a
574 visually unambiguous form. The characters listed in the Base Defini‐
575 tions volume of IEEE Std 1003.1-2001, Table 5-1, Escape Sequences and
576 Associated Actions ( '\\', '\a', '\b', '\f', '\r', '\t', '\v' ) shall
577 be written as the corresponding escape sequence; the '\n' in that table
578 is not applicable. Non-printable characters not in the table shall be
579 written as one three-digit octal number (with a preceding backslash
580 character) for each byte in the character (most significant byte
581 first). If the size of a byte on the system is greater than nine bits,
582 the format used for non-printable characters is implementation-defined.
583 Long lines shall be folded, with the point of folding indicated by
585 <newline> preceded by a backslash; the length at which folding occurs
586 is unspecified, but should be appropriate for the output device. The
587 end of each line shall be marked with a '$', and '$' characters within
588 the text shall be written with a preceding backslash. An l command can
589 be appended to any other command other than e, E, f, q, Q, r, w, or !.
590 The current line number shall be set to the address of the last line
591 written.
592 Move Command
594 Synopsis:
595 (.,.)maddress
598 The m command shall reposition the addressed lines after the line
601 addressed by address. Address 0 shall be valid for address and cause
602 the addressed lines to be moved to the beginning of the buffer. It
603 shall be an error if address address falls within the range of moved
604 lines. The current line number shall be set to the address of the last
605 line moved.
606 Number Command
608 Synopsis:
609 (.,.)n
612 The n command shall write to standard output the addressed lines, pre‐
615 ceding each line by its line number and a <tab>; the current line num‐
616 ber shall be set to the address of the last line written. The n command
617 can be appended to any command other than e, E, f, q, Q, r, w, or !.
618 Print Command
620 Synopsis:
621 (.,.)p
624 The p command shall write to standard output the addressed lines; the
627 current line number shall be set to the address of the last line writ‐
628 ten. The p command can be appended to any command other than e, E, f,
629 q, Q, r, w, or !.
630 Prompt Command
632 Synopsis:
633 P
636 The P command shall cause ed to prompt with an asterisk ( '*' ) (or
639 string, if -p is specified) for all subsequent commands. The P command
640 alternatively shall turn this mode on and off; it shall be initially on
641 if the -p option is specified; otherwise, off. The current line number
642 shall be unchanged.
643 Quit Command
645 Synopsis:
646 q
649 The q command shall cause ed to exit. If the buffer has changed since
652 the last time the entire buffer was written, the user shall be warned,
653 as described previously.
654 Quit Without Checking Command
656 Synopsis:
657 Q
660 The Q command shall cause ed to exit without checking whether changes
663 have been made in the buffer since the last w command.
664 Read Command
666 Synopsis:
667 ($)r [file]
670 The r command shall read in the file named by the pathname file and
673 append it after the addressed line. If no file argument is given, the
674 currently remembered pathname, if any, shall be used (see the e and f
675 commands). The currently remembered pathname shall not be changed
676 unless there is no remembered pathname. Address 0 shall be valid for r
677 and shall cause the file to be read at the beginning of the buffer. If
678 the read is successful, and -s was not specified, the number of bytes
679 read shall be written to standard output in the following format:
680 "%d\n", <number of bytes read>
683 The current line number shall be set to the address of the last line
685 read in. If file is replaced by '!', the rest of the line shall be
686 taken to be a shell command line whose output is to be read. Such a
687 shell command line shall not be remembered as the current pathname.
688 Substitute Command
690 Synopsis:
691 (.,.)s/RE/replacement/flags
694 The s command shall search each addressed line for an occurrence of the
697 specified RE and replace either the first or all (non-overlapped)
698 matched strings with the replacement; see the following description of
699 the g suffix. It is an error if the substitution fails on every
700 addressed line. Any character other than <space> or <newline> can be
701 used instead of a slash to delimit the RE and the replacement. Within
702 the RE, the RE delimiter itself can be used as a literal character if
703 it is preceded by a backslash. The current line shall be set to the
704 address of the last line on which a substitution occurred.
705 An ampersand ( '&' ) appearing in the replacement shall be replaced by
707 the string matching the RE on the current line. The special meaning of
708 '&' in this context can be suppressed by preceding it by backslash. As
709 a more general feature, the characters '\n', where n is a digit, shall
710 be replaced by the text matched by the corresponding back-reference
711 expression. When the character '%' is the only character in the
712 replacement, the replacement used in the most recent substitute command
713 shall be used as the replacement in the current substitute command; if
714 there was no previous substitute command, the use of '%' in this manner
715 shall be an error. The '%' shall lose its special meaning when it is in
716 a replacement string of more than one character or is preceded by a
717 backslash. For each backslash ( '\' ) encountered in scanning replace‐
718 ment from beginning to end, the following character shall lose its spe‐
719 cial meaning (if any). It is unspecified what special meaning is given
720 to any character other than '&', '\', '%', or digits.
721 A line can be split by substituting a <newline> into it. The applica‐
723 tion shall ensure it escapes the <newline> in the replacement by pre‐
724 ceding it by backslash. Such substitution cannot be done as part of a g
725 or v command list. The current line number shall be set to the address
726 of the last line on which a substitution is performed. If no substitu‐
727 tion is performed, the current line number shall be unchanged. If a
728 line is split, a substitution shall be considered to have been per‐
729 formed on each of the new lines for the purpose of determining the new
730 current line number. A substitution shall be considered to have been
731 performed even if the replacement string is identical to the string
732 that it replaces.
733 The application shall ensure that the value of flags is zero or more
735 of:
736 count Substitute for the countth occurrence only of the RE found on
738 each addressed line.
739 g Globally substitute for all non-overlapping instances of the RE
741 rather than just the first one. If both g and count are speci‐
742 fied, the results are unspecified.
743 l Write to standard output the final line in which a substitution
745 was made. The line shall be written in the format specified for
746 the l command.
747 n Write to standard output the final line in which a substitution
749 was made. The line shall be written in the format specified for
750 the n command.
751 p Write to standard output the final line in which a substitution
753 was made. The line shall be written in the format specified for
754 the p command.
755 Copy Command
758 Synopsis:
759 (.,.)taddress
762 The t command shall be equivalent to the m command, except that a copy
765 of the addressed lines shall be placed after address address (which can
766 be 0); the current line number shall be set to the address of the last
767 line added.
768 Undo Command
770 Synopsis:
771 u
774 The u command shall nullify the effect of the most recent command that
777 modified anything in the buffer, namely the most recent a, c, d, g, i,
778 j, m, r, s, t, u, v, G, or V command. All changes made to the buffer by
779 a g, G, v, or V global command shall be undone as a single change; if
780 no changes were made by the global command (such as with g/RE/ p), the
781 u command shall have no effect. The current line number shall be set to
782 the value it had immediately before the command being undone started.
783 Global Non-Matched Command
785 Synopsis:
786 (1,$)v/RE/command list
789 This command shall be equivalent to the global command g except that
792 the lines that are marked during the first step shall be those for
793 which the line excluding the terminating <newline> does not match the
794 RE.
795 Interactive Global Not-Matched Command
797 Synopsis:
798 (1,$)V/RE/
801 This command shall be equivalent to the interactive global command G
804 except that the lines that are marked during the first step shall be
805 those for which the line excluding the terminating <newline> does not
806 match the RE.
807 Write Command
809 Synopsis:
810 (1,$)w [file]
813 The w command shall write the addressed lines into the file named by
816 the pathname file. The command shall create the file, if it does not
817 exist, or shall replace the contents of the existing file. The cur‐
818 rently remembered pathname shall not be changed unless there is no
819 remembered pathname. If no pathname is given, the currently remembered
820 pathname, if any, shall be used (see the e and f commands); the current
821 line number shall be unchanged. If the command is successful, the num‐
822 ber of bytes written shall be written to standard output, unless the -s
823 option was specified, in the following format:
824 "%d\n", <number of bytes written>
827 If file begins with '!', the rest of the line shall be taken to be a
829 shell command line whose standard input shall be the addressed lines.
830 Such a shell command line shall not be remembered as the current path‐
831 name. This usage of the write command with '!' shall not be considered
832 as a "last w command that wrote the entire buffer", as described previ‐
833 ously; thus, this alone shall not prevent the warning to the user if an
834 attempt is made to destroy the editor buffer via the e or q commands.
835 Line Number Command
837 Synopsis:
838 ($)=
841 The line number of the addressed line shall be written to standard out‐
844 put in the following format:
845 "%d\n", <line number>
848 The current line number shall be unchanged by this command.
850 Shell Escape Command
852 Synopsis:
853 !command
856 The remainder of the line after the '!' shall be sent to the command
859 interpreter to be interpreted as a shell command line. Within the text
860 of that shell command line, the unescaped character '%' shall be
861 replaced with the remembered pathname; if a '!' appears as the first
862 character of the command, it shall be replaced with the text of the
863 previous shell command executed via '!' . Thus, "!!" shall repeat the
864 previous !command. If any replacements of '%' or '!' are performed, the
865 modified line shall be written to the standard output before command is
866 executed. The ! command shall write:
867 "!\n"
870 to standard output upon completion, unless the -s option is specified.
872 The current line number shall be unchanged.
873 Null Command
875 Synopsis:
876 (.+1)
879 An address alone on a line shall cause the addressed line to be writ‐
882 ten. A <newline> alone shall be equivalent to "+1p" . The current line
883 number shall be set to the address of the written line.
884
886 The following exit values shall be returned:
887 0 Successful completion without any file or command errors.
889 >0 An error occurred.
891
894 When an error in the input script is encountered, or when an error is
895 detected that is a consequence of the data (not) present in the file or
896 due to an external condition such as a read or write error:
897 * If the standard input is a terminal device file, all input shall be
899 flushed, and a new command read.
900 * If the standard input is a regular file, ed shall terminate with a
902 non-zero exit status.
903 The following sections are informative.
905
907 Because of the extremely terse nature of the default error messages,
908 the prudent script writer begins the ed input commands with an H com‐
909 mand, so that if any errors do occur at least some clue as to the cause
910 is made available.
911 In previous versions, an obsolescent - option was described. This is
913 no longer specified. Applications should use the -s option. Using - as
914 a file operand now produces unspecified results. This allows implemen‐
915 tations to continue to support the former required behavior.
916
918 None.
919
921 The initial description of this utility was adapted from the SVID. It
922 contains some features not found in Version 7 or BSD-derived systems.
923 Some of the differences between the POSIX and BSD ed utilities include,
924 but need not be limited to:
925 * The BSD - option does not suppress the '!' prompt after a ! command.
927 * BSD does not support the special meanings of the '%' and '!' char‐
929 acters within a ! command.
930 * BSD does not support the addresses ';' and ',' .
932 * BSD allows the command/suffix pairs pp, ll, and so on, which are
934 unspecified in this volume of IEEE Std 1003.1-2001.
935 * BSD does not support the '!' character part of the e, r, or w com‐
937 mands.
938 * A failed g command in BSD sets the line number to the last line
940 searched if there are no matches.
941 * BSD does not default the command list to the p command.
943 * BSD does not support the G, h, H, n, or V commands.
945 * On BSD, if there is no inserted text, the insert command changes the
947 current line to the referenced line -1; that is, the line before the
948 specified line.
949 * On BSD, the join command with only a single address changes the cur‐
951 rent line to that address.
952 * BSD does not support the P command; moreover, in BSD it is synony‐
954 mous with the p command.
955 * BSD does not support the undo of the commands j, m, r, s, or t.
957 * The Version 7 ed command W, and the BSD ed commands W, wq, and z are
959 not present in this volume of IEEE Std 1003.1-2001.
960 The -s option was added to allow the functionality of the now withdrawn
962 - option in a manner compatible with the Utility Syntax Guidelines.
963 In early proposals there was a limit, {ED_FILE_MAX}, that described the
965 historical limitations of some ed utilities in their handling of large
966 files; some of these have had problems with files larger than 100000
967 bytes. It was this limitation that prompted much of the desire to
968 include a split command in this volume of IEEE Std 1003.1-2001. Since
969 this limit was removed, this volume of IEEE Std 1003.1-2001 requires
970 that implementations document the file size limits imposed by ed in the
971 conformance document. The limit {ED_LINE_MAX} was also removed; there‐
972 fore, the global limit {LINE_MAX} is used for input and output lines.
973 The manner in which the l command writes non-printable characters was
975 changed to avoid the historical backspace-overstrike method. On video
976 display terminals, the overstrike is ambiguous because most terminals
977 simply replace overstruck characters, making the l format not useful
978 for its intended purpose of unambiguously understanding the content of
979 the line. The historical backslash escapes were also ambiguous. (The
980 string "a\0011" could represent a line containing those six characters
981 or a line containing the three characters 'a', a byte with a binary
982 value of 1, and a 1.) In the format required here, a backslash appear‐
983 ing in the line is written as "\\" so that the output is truly unam‐
984 biguous. The method of marking the ends of lines was adopted from the
985 ex editor and is required for any line ending in <space>s; the '$' is
986 placed on all lines so that a real '$' at the end of a line cannot be
987 misinterpreted.
988 Systems with bytes too large to fit into three octal digits must devise
990 other means of displaying non-printable characters. Consideration was
991 given to requiring that the number of octal digits be large enough to
992 hold a byte, but this seemed to be too confusing for applications on
993 the vast majority of systems where three digits are adequate. It would
994 be theoretically possible for the application to use the getconf util‐
995 ity to find out the CHAR_BIT value and deal with such an algorithm;
996 however, there is really no portable way that an application can use
997 the octal values of the bytes across various coded character sets, so
998 the additional specification was not worthwhile.
999 The description of how a NUL is written was removed. The NUL character
1001 cannot be in text files, and this volume of IEEE Std 1003.1-2001 should
1002 not dictate behavior in the case of undefined, erroneous input.
1003 Unlike some of the other editing utilities, the filenames accepted by
1005 the E, e, R, and r commands are not patterns.
1006 Early proposals stated that the -p option worked only when standard
1008 input was associated with a terminal device. This has been changed to
1009 conform to historical implementations, thereby allowing applications to
1010 interpose themselves between a user and the ed utility.
1011 The form of the substitute command that uses the n suffix was limited
1013 in some historical documentation (where this was described incorrectly
1014 as "backreferencing"). This limit has been omitted because there is no
1015 reason why an editor processing lines of {LINE_MAX} length should have
1016 this restriction. The command s/x/X/2047 should be able to substitute
1017 the 2047th occurrence of 'x' on a line.
1018 The use of printing commands with printing suffixes (such as pn, lp,
1020 and so on) was made unspecified because BSD-based systems allow this,
1021 whereas System V does not.
1022 Some BSD-based systems exit immediately upon receipt of end-of-file if
1024 all of the lines in the file have been deleted. Since this volume of
1025 IEEE Std 1003.1-2001 refers to the q command in this instance, such
1026 behavior is not allowed.
1027 Some historical implementations returned exit status zero even if com‐
1029 mand errors had occurred; this is not allowed by this volume of
1030 IEEE Std 1003.1-2001.
1031 Some historical implementations contained a bug that allowed a single
1033 period to be entered in input mode as <backslash> <period> <newline>.
1034 This is not allowed by ed because there is no description of escaping
1035 any of the characters in input mode; backslashes are entered into the
1036 buffer exactly as typed. The typical method of entering a single period
1037 has been to precede it with another character and then use the substi‐
1038 tute command to delete that character.
1039 It is difficult under some modes of some versions of historical operat‐
1041 ing system terminal drivers to distinguish between an end-of-file con‐
1042 dition and terminal disconnect. IEEE Std 1003.1-2001 does not require
1043 implementations to distinguish between the two situations, which per‐
1044 mits historical implementations of the ed utility on historical plat‐
1045 forms to conform. Implementations are encouraged to distinguish
1046 between the two, if possible, and take appropriate action on terminal
1047 disconnect.
1048 Historically, ed accepted a zero address for the a and r commands in
1050 order to insert text at the start of the edit buffer. When the buffer
1051 was empty the command .= returned zero. IEEE Std 1003.1-2001 requires
1052 conformance to historical practice.
1053 For consistency with the a and r commands and better user functional‐
1055 ity, the i and c commands must also accept an address of 0, in which
1056 case 0i is treated as 1i and likewise for the c command.
1057 All of the following are valid addresses:
1059 +++ Three lines after the current line.
1061 /pattern/-
1063 One line before the next occurrence of pattern.
1064 -2 Two lines before the current line.
1066 3 ---- 2
1068 Line one (note the intermediate negative address).
1069 1 2 3 Line six.
1071 Any number of addresses can be provided to commands taking addresses;
1074 for example, "1,2,3,4,5p" prints lines 4 and 5, because two is the
1075 greatest valid number of addresses accepted by the print command. This,
1076 in combination with the semicolon delimiter, permits users to create
1077 commands based on ordered patterns in the file. For example, the com‐
1078 mand "3;/foo/;+2p" will display the first line after line 3 that con‐
1079 tains the pattern foo, plus the next two lines. Note that the address
1080 "3;" must still be evaluated before being discarded, because the search
1081 origin for the "/foo/" command depends on this.
1082 Historically, ed disallowed address chains, as discussed above, con‐
1084 sisting solely of comma or semicolon separators; for example, ",,," or
1085 ";;;" were considered an error. For consistency of address specifica‐
1086 tion, this restriction is removed. The following table lists some of
1087 the address forms now possible:
1088 Address Addr1 Addr2 Status Comment
1090 7, 7 7 Historical
1091 7,5, 5 5 Historical
1092 7,5,9 5 9 Historical
1093 7,9 7 9 Historical
1094 7,+ 7 8 Historical
1095 , 1 $ Historical
1096 ,7 1 7 Extension
1097 ,, $ $ Extension
1098 ,; $ $ Extension
1099 7; 7 7 Historical
1100 7;5; 5 5 Historical
1101 7;5;9 5 9 Historical
1102 7;5,9 5 9 Historical
1103 7;$;4 $ 4 Historical Valid, but erroneous.
1104 7;9 7 9 Historical
1105 7;+ 7 8 Historical
1106 ; . $ Historical
1107 ;7 . 7 Extension
1108 ;; $ $ Extension
1109 ;, $ $ Extension
1110 Historically, values could be added to addresses by including them
1112 after one or more <blank>s; for example, "3 - 5p" wrote the seventh
1113 line of the file, and "/foo/ 5" was the same as "5 /foo/" . However,
1114 only absolute values could be added; for example, "5 /foo/" was an
1115 error. IEEE Std 1003.1-2001 requires conformance to historical prac‐
1116 tice.
1117 Historically, ed accepted the '^' character as an address, in which
1119 case it was identical to the hyphen character. IEEE Std 1003.1-2001
1120 does not require or prohibit this behavior.
1121
1123 None.
1124
1126 Utility Description Defaults, ex, sed, sh, vi
1127
1129 Portions of this text are reprinted and reproduced in electronic form
1130 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
1131 -- Portable Operating System Interface (POSIX), The Open Group Base
1132 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
1133 Electrical and Electronics Engineers, Inc and The Open Group. In the
1134 event of any discrepancy between this version and the original IEEE and
1135 The Open Group Standard, the original IEEE and The Open Group Standard
1136 is the referee document. The original Standard can be obtained online
1137 at http://www.opengroup.org/unix/online.html .
1138IEEE/The Open Group 2003 ED(1P)