Annotation of embedaddon/readline/doc/history.3, revision 1.1.1.1
1.1 misho 1: .\"
2: .\" MAN PAGE COMMENTS to
3: .\"
4: .\" Chet Ramey
5: .\" Information Network Services
6: .\" Case Western Reserve University
7: .\" chet.ramey@case.edu
8: .\"
9: .\" Last Change: Thu Thu Jun 27 10:34:44 EDT 2013
10: .\"
11: .TH HISTORY 3 "2013 June 27" "GNU History 6.3"
12: .\"
13: .\" File Name macro. This used to be `.PN', for Path Name,
14: .\" but Sun doesn't seem to like that very much.
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16: .de FN
17: \fI\|\\$1\|\fP
18: ..
19: .ds lp \fR\|(\fP
20: .ds rp \fR\|)\fP
21: .\" FnN return-value fun-name N arguments
22: .de Fn1
23: \fI\\$1\fP \fB\\$2\fP \\*(lp\fI\\$3\fP\\*(rp
24: .br
25: ..
26: .de Fn2
27: .if t \fI\\$1\fP \fB\\$2\fP \\*(lp\fI\\$3,\|\\$4\fP\\*(rp
28: .if n \fI\\$1\fP \fB\\$2\fP \\*(lp\fI\\$3, \\$4\fP\\*(rp
29: .br
30: ..
31: .de Fn3
32: .if t \fI\\$1\fP \fB\\$2\fP \\*(lp\fI\\$3,\|\\$4,\|\\$5\fP\|\\*(rp
33: .if n \fI\\$1\fP \fB\\$2\fP \\*(lp\fI\\$3, \\$4, \\$5\fP\\*(rp
34: .br
35: ..
36: .de Vb
37: \fI\\$1\fP \fB\\$2\fP
38: .br
39: ..
40: .SH NAME
41: history \- GNU History Library
42: .SH COPYRIGHT
43: .if t The GNU History Library is Copyright \(co 1989-2011 by the Free Software Foundation, Inc.
44: .if n The GNU History Library is Copyright (C) 1989-2011 by the Free Software Foundation, Inc.
45: .SH DESCRIPTION
46: Many programs read input from the user a line at a time. The GNU
47: History library is able to keep track of those lines, associate arbitrary
48: data with each line, and utilize information from previous lines in
49: composing new ones.
50: .PP
51: .SH "HISTORY EXPANSION"
52: .PP
53: The history library supports a history expansion feature that
54: is identical to the history expansion in
55: .BR bash.
56: This section describes what syntax features are available.
57: .PP
58: History expansions introduce words from the history list into
59: the input stream, making it easy to repeat commands, insert the
60: arguments to a previous command into the current input line, or
61: fix errors in previous commands quickly.
62: .PP
63: History expansion is usually performed immediately after a complete line
64: is read.
65: It takes place in two parts.
66: The first is to determine which line from the history list
67: to use during substitution.
68: The second is to select portions of that line for inclusion into
69: the current one.
70: The line selected from the history is the \fIevent\fP,
71: and the portions of that line that are acted upon are \fIwords\fP.
72: Various \fImodifiers\fP are available to manipulate the selected words.
73: The line is broken into words in the same fashion as \fBbash\fP
74: does when reading input,
75: so that several words that would otherwise be separated
76: are considered one word when surrounded by quotes (see the
77: description of \fBhistory_tokenize()\fP below).
78: History expansions are introduced by the appearance of the
79: history expansion character, which is \^\fB!\fP\^ by default.
80: Only backslash (\^\fB\e\fP\^) and single quotes can quote
81: the history expansion character.
82: .SS Event Designators
83: .PP
84: An event designator is a reference to a command line entry in the
85: history list.
86: Unless the reference is absolute, events are relative to the current
87: position in the history list.
88: .PP
89: .PD 0
90: .TP
91: .B !
92: Start a history substitution, except when followed by a
93: .BR blank ,
94: newline, = or (.
95: .TP
96: .B !\fIn\fR
97: Refer to command line
98: .IR n .
99: .TP
100: .B !\-\fIn\fR
101: Refer to the current command minus
102: .IR n .
103: .TP
104: .B !!
105: Refer to the previous command. This is a synonym for `!\-1'.
106: .TP
107: .B !\fIstring\fR
108: Refer to the most recent command
109: preceding the current position in the history list
110: starting with
111: .IR string .
112: .TP
113: .B !?\fIstring\fR\fB[?]\fR
114: Refer to the most recent command
115: preceding the current position in the history list
116: containing
117: .IR string .
118: The trailing \fB?\fP may be omitted if
119: .I string
120: is followed immediately by a newline.
121: .TP
122: .B \d\s+2^\s-2\u\fIstring1\fP\d\s+2^\s-2\u\fIstring2\fP\d\s+2^\s-2\u
123: Quick substitution. Repeat the last command, replacing
124: .I string1
125: with
126: .IR string2 .
127: Equivalent to
128: ``!!:s/\fIstring1\fP/\fIstring2\fP/''
129: (see \fBModifiers\fP below).
130: .TP
131: .B !#
132: The entire command line typed so far.
133: .PD
134: .SS Word Designators
135: .PP
136: Word designators are used to select desired words from the event.
137: A
138: .B :
139: separates the event specification from the word designator.
140: It may be omitted if the word designator begins with a
141: .BR ^ ,
142: .BR $ ,
143: .BR * ,
144: .BR \- ,
145: or
146: .BR % .
147: Words are numbered from the beginning of the line,
148: with the first word being denoted by 0 (zero).
149: Words are inserted into the current line separated by single spaces.
150: .PP
151: .PD 0
152: .TP
153: .B 0 (zero)
154: The zeroth word. For the shell, this is the command
155: word.
156: .TP
157: .I n
158: The \fIn\fRth word.
159: .TP
160: .B ^
161: The first argument. That is, word 1.
162: .TP
163: .B $
164: The last word. This is usually the last argument, but will expand to the
165: zeroth word if there is only one word in the line.
166: .TP
167: .B %
168: The word matched by the most recent `?\fIstring\fR?' search.
169: .TP
170: .I x\fB\-\fPy
171: A range of words; `\-\fIy\fR' abbreviates `0\-\fIy\fR'.
172: .TP
173: .B *
174: All of the words but the zeroth. This is a synonym
175: for `\fI1\-$\fP'. It is not an error to use
176: .B *
177: if there is just one
178: word in the event; the empty string is returned in that case.
179: .TP
180: .B x*
181: Abbreviates \fIx\-$\fP.
182: .TP
183: .B x\-
184: Abbreviates \fIx\-$\fP like \fBx*\fP, but omits the last word.
185: .PD
186: .PP
187: If a word designator is supplied without an event specification, the
188: previous command is used as the event.
189: .SS Modifiers
190: .PP
191: After the optional word designator, there may appear a sequence of
192: one or more of the following modifiers, each preceded by a `:'.
193: .PP
194: .PD 0
195: .PP
196: .TP
197: .B h
198: Remove a trailing file name component, leaving only the head.
199: .TP
200: .B t
201: Remove all leading file name components, leaving the tail.
202: .TP
203: .B r
204: Remove a trailing suffix of the form \fI.xxx\fP, leaving the
205: basename.
206: .TP
207: .B e
208: Remove all but the trailing suffix.
209: .TP
210: .B p
211: Print the new command but do not execute it.
212: .TP
213: .B q
214: Quote the substituted words, escaping further substitutions.
215: .TP
216: .B x
217: Quote the substituted words as with
218: .BR q ,
219: but break into words at
220: .B blanks
221: and newlines.
222: .TP
223: .B s/\fIold\fP/\fInew\fP/
224: Substitute
225: .I new
226: for the first occurrence of
227: .I old
228: in the event line. Any delimiter can be used in place of /. The
229: final delimiter is optional if it is the last character of the
230: event line. The delimiter may be quoted in
231: .I old
232: and
233: .I new
234: with a single backslash. If & appears in
235: .IR new ,
236: it is replaced by
237: .IR old .
238: A single backslash will quote the &. If
239: .I old
240: is null, it is set to the last
241: .I old
242: substituted, or, if no previous history substitutions took place,
243: the last
244: .I string
245: in a
246: .B !?\fIstring\fR\fB[?]\fR
247: search.
248: .TP
249: .B &
250: Repeat the previous substitution.
251: .TP
252: .B g
253: Cause changes to be applied over the entire event line. This is
254: used in conjunction with `\fB:s\fP' (e.g., `\fB:gs/\fIold\fP/\fInew\fP/\fR')
255: or `\fB:&\fP'. If used with
256: `\fB:s\fP', any delimiter can be used
257: in place of /, and the final delimiter is optional
258: if it is the last character of the event line.
259: An \fBa\fP may be used as a synonym for \fBg\fP.
260: .TP
261: .B G
262: Apply the following `\fBs\fP' modifier once to each word in the event line.
263: .PD
264: .SH "PROGRAMMING WITH HISTORY FUNCTIONS"
265: This section describes how to use the History library in other programs.
266: .SS Introduction to History
267: .PP
268: The programmer using the History library has available functions
269: for remembering lines on a history list, associating arbitrary data
270: with a line, removing lines from the list, searching through the list
271: for a line containing an arbitrary text string, and referencing any line
272: in the list directly. In addition, a history \fIexpansion\fP function
273: is available which provides for a consistent user interface across
274: different programs.
275: .PP
276: The user using programs written with the History library has the
277: benefit of a consistent user interface with a set of well-known
278: commands for manipulating the text of previous lines and using that text
279: in new commands. The basic history manipulation commands are
280: identical to
281: the history substitution provided by \fBbash\fP.
282: .PP
283: If the programmer desires, he can use the Readline library, which
284: includes some history manipulation by default, and has the added
285: advantage of command line editing.
286: .PP
287: Before declaring any functions using any functionality the History
288: library provides in other code, an application writer should include
289: the file
290: .FN <readline/history.h>
291: in any file that uses the
292: History library's features. It supplies extern declarations for all
293: of the library's public functions and variables, and declares all of
294: the public data structures.
295:
296: .SS History Storage
297: .PP
298: The history list is an array of history entries. A history entry is
299: declared as follows:
300: .PP
301: .Vb "typedef void *" histdata_t;
302: .PP
303: .nf
304: typedef struct _hist_entry {
305: char *line;
306: char *timestamp;
307: histdata_t data;
308: } HIST_ENTRY;
309: .fi
310: .PP
311: The history list itself might therefore be declared as
312: .PP
313: .Vb "HIST_ENTRY **" the_history_list;
314: .PP
315: The state of the History library is encapsulated into a single structure:
316: .PP
317: .nf
318: /*
319: * A structure used to pass around the current state of the history.
320: */
321: typedef struct _hist_state {
322: HIST_ENTRY **entries; /* Pointer to the entries themselves. */
323: int offset; /* The location pointer within this array. */
324: int length; /* Number of elements within this array. */
325: int size; /* Number of slots allocated to this array. */
326: int flags;
327: } HISTORY_STATE;
328: .fi
329: .PP
330: If the flags member includes \fBHS_STIFLED\fP, the history has been
331: stifled.
332: .SH "History Functions"
333: .PP
334: This section describes the calling sequence for the various functions
335: exported by the GNU History library.
336: .SS Initializing History and State Management
337: This section describes functions used to initialize and manage
338: the state of the History library when you want to use the history
339: functions in your program.
340:
341: .Fn1 void using_history void
342: Begin a session in which the history functions might be used. This
343: initializes the interactive variables.
344:
345: .Fn1 "HISTORY_STATE *" history_get_history_state void
346: Return a structure describing the current state of the input history.
347:
348: .Fn1 void history_set_history_state "HISTORY_STATE *state"
349: Set the state of the history list according to \fIstate\fP.
350:
351: .SS History List Management
352:
353: These functions manage individual entries on the history list, or set
354: parameters managing the list itself.
355:
356: .Fn1 void add_history "const char *string"
357: Place \fIstring\fP at the end of the history list. The associated data
358: field (if any) is set to \fBNULL\fP.
359:
360: .Fn1 void add_history_time "const char *string"
361: Change the time stamp associated with the most recent history entry to
362: \fIstring\fP.
363:
364: .Fn1 "HIST_ENTRY *" remove_history "int which"
365: Remove history entry at offset \fIwhich\fP from the history. The
366: removed element is returned so you can free the line, data,
367: and containing structure.
368:
369: .Fn1 "histdata_t" free_history_entry "HIST_ENTRY *histent"
370: Free the history entry \fIhistent\fP and any history library private
371: data associated with it. Returns the application-specific data
372: so the caller can dispose of it.
373:
374: .Fn3 "HIST_ENTRY *" replace_history_entry "int which" "const char *line" "histdata_t data"
375: Make the history entry at offset \fIwhich\fP have \fIline\fP and \fIdata\fP.
376: This returns the old entry so the caller can dispose of any
377: application-specific data. In the case
378: of an invalid \fIwhich\fP, a \fBNULL\fP pointer is returned.
379:
380: .Fn1 void clear_history "void"
381: Clear the history list by deleting all the entries.
382:
383: .Fn1 void stifle_history "int max"
384: Stifle the history list, remembering only the last \fImax\fP entries.
385:
386: .Fn1 int unstifle_history "void"
387: Stop stifling the history. This returns the previously-set
388: maximum number of history entries (as set by \fBstifle_history()\fP).
389: history was stifled. The value is positive if the history was
390: stifled, negative if it wasn't.
391:
392: .Fn1 int history_is_stifled "void"
393: Returns non-zero if the history is stifled, zero if it is not.
394:
395: .SS Information About the History List
396:
397: These functions return information about the entire history list or
398: individual list entries.
399:
400: .Fn1 "HIST_ENTRY **" history_list "void"
401: Return a \fBNULL\fP terminated array of \fIHIST_ENTRY *\fP which is the
402: current input history. Element 0 of this list is the beginning of time.
403: If there is no history, return \fBNULL\fP.
404:
405: .Fn1 int where_history "void"
406: Returns the offset of the current history element.
407:
408: .Fn1 "HIST_ENTRY *" current_history "void"
409: Return the history entry at the current position, as determined by
410: \fBwhere_history()\fP. If there is no entry there, return a \fBNULL\fP
411: pointer.
412:
413: .Fn1 "HIST_ENTRY *" history_get "int offset"
414: Return the history entry at position \fIoffset\fP, starting from
415: \fBhistory_base\fP.
416: If there is no entry there, or if \fIoffset\fP
417: is greater than the history length, return a \fBNULL\fP pointer.
418:
419: .Fn1 "time_t" history_get_time "HIST_ENTRY *"
420: Return the time stamp associated with the history entry passed as the argument.
421:
422: .Fn1 int history_total_bytes "void"
423: Return the number of bytes that the primary history entries are using.
424: This function returns the sum of the lengths of all the lines in the
425: history.
426:
427: .SS Moving Around the History List
428:
429: These functions allow the current index into the history list to be
430: set or changed.
431:
432: .Fn1 int history_set_pos "int pos"
433: Set the current history offset to \fIpos\fP, an absolute index
434: into the list.
435: Returns 1 on success, 0 if \fIpos\fP is less than zero or greater
436: than the number of history entries.
437:
438: .Fn1 "HIST_ENTRY *" previous_history "void"
439: Back up the current history offset to the previous history entry, and
440: return a pointer to that entry. If there is no previous entry, return
441: a \fBNULL\fP pointer.
442:
443: .Fn1 "HIST_ENTRY *" next_history "void"
444: Move the current history offset forward to the next history entry, and
445: return the a pointer to that entry. If there is no next entry, return
446: a \fBNULL\fP pointer.
447:
448: .SS Searching the History List
449:
450: These functions allow searching of the history list for entries containing
451: a specific string. Searching may be performed both forward and backward
452: from the current history position. The search may be \fIanchored\fP,
453: meaning that the string must match at the beginning of the history entry.
454:
455: .Fn2 int history_search "const char *string" "int direction"
456: Search the history for \fIstring\fP, starting at the current history offset.
457: If \fIdirection\fP is less than 0, then the search is through
458: previous entries, otherwise through subsequent entries.
459: If \fIstring\fP is found, then
460: the current history index is set to that history entry, and the value
461: returned is the offset in the line of the entry where
462: \fIstring\fP was found. Otherwise, nothing is changed, and a -1 is
463: returned.
464:
465: .Fn2 int history_search_prefix "const char *string" "int direction"
466: Search the history for \fIstring\fP, starting at the current history
467: offset. The search is anchored: matching lines must begin with
468: \fIstring\fP. If \fIdirection\fP is less than 0, then the search is
469: through previous entries, otherwise through subsequent entries.
470: If \fIstring\fP is found, then the
471: current history index is set to that entry, and the return value is 0.
472: Otherwise, nothing is changed, and a -1 is returned.
473:
474: .Fn3 int history_search_pos "const char *string" "int direction" "int pos"
475: Search for \fIstring\fP in the history list, starting at \fIpos\fP, an
476: absolute index into the list. If \fIdirection\fP is negative, the search
477: proceeds backward from \fIpos\fP, otherwise forward. Returns the absolute
478: index of the history element where \fIstring\fP was found, or -1 otherwise.
479:
480: .SS Managing the History File
481: The History library can read the history from and write it to a file.
482: This section documents the functions for managing a history file.
483:
484: .Fn1 int read_history "const char *filename"
485: Add the contents of \fIfilename\fP to the history list, a line at a time.
486: If \fIfilename\fP is \fBNULL\fP, then read from \fI~/.history\fP.
487: Returns 0 if successful, or \fBerrno\fP if not.
488:
489: .Fn3 int read_history_range "const char *filename" "int from" "int to"
490: Read a range of lines from \fIfilename\fP, adding them to the history list.
491: Start reading at line \fIfrom\fP and end at \fIto\fP.
492: If \fIfrom\fP is zero, start at the beginning. If \fIto\fP is less than
493: \fIfrom\fP, then read until the end of the file. If \fIfilename\fP is
494: \fBNULL\fP, then read from \fI~/.history\fP. Returns 0 if successful,
495: or \fBerrno\fP if not.
496:
497: .Fn1 int write_history "const char *filename"
498: Write the current history to \fIfilename\fP, overwriting \fIfilename\fP
499: if necessary.
500: If \fIfilename\fP is \fBNULL\fP, then write the history list to \fI~/.history\fP.
501: Returns 0 on success, or \fBerrno\fP on a read or write error.
502:
503:
504: .Fn2 int append_history "int nelements" "const char *filename"
505: Append the last \fInelements\fP of the history list to \fIfilename\fP.
506: If \fIfilename\fP is \fBNULL\fP, then append to \fI~/.history\fP.
507: Returns 0 on success, or \fBerrno\fP on a read or write error.
508:
509: .Fn2 int history_truncate_file "const char *filename" "int nlines"
510: Truncate the history file \fIfilename\fP, leaving only the last
511: \fInlines\fP lines.
512: If \fIfilename\fP is \fBNULL\fP, then \fI~/.history\fP is truncated.
513: Returns 0 on success, or \fBerrno\fP on failure.
514:
515: .SS History Expansion
516:
517: These functions implement history expansion.
518:
519: .Fn2 int history_expand "char *string" "char **output"
520: Expand \fIstring\fP, placing the result into \fIoutput\fP, a pointer
521: to a string. Returns:
522: .RS
523: .PD 0
524: .TP
525: 0
526: If no expansions took place (or, if the only change in
527: the text was the removal of escape characters preceding the history expansion
528: character);
529: .TP
530: 1
531: if expansions did take place;
532: .TP
533: -1
534: if there was an error in expansion;
535: .TP
536: 2
537: if the returned line should be displayed, but not executed,
538: as with the \fB:p\fP modifier.
539: .PD
540: .RE
541: If an error ocurred in expansion, then \fIoutput\fP contains a descriptive
542: error message.
543:
544: .Fn3 "char *" get_history_event "const char *string" "int *cindex" "int qchar"
545: Returns the text of the history event beginning at \fIstring\fP +
546: \fI*cindex\fP. \fI*cindex\fP is modified to point to after the event
547: specifier. At function entry, \fIcindex\fP points to the index into
548: \fIstring\fP where the history event specification begins. \fIqchar\fP
549: is a character that is allowed to end the event specification in addition
550: to the ``normal'' terminating characters.
551:
552: .Fn1 "char **" history_tokenize "const char *string"
553: Return an array of tokens parsed out of \fIstring\fP, much as the
554: shell might.
555: The tokens are split on the characters in the
556: \fBhistory_word_delimiters\fP variable,
557: and shell quoting conventions are obeyed.
558:
559: .Fn3 "char *" history_arg_extract "int first" "int last" "const char *string"
560: Extract a string segment consisting of the \fIfirst\fP through \fIlast\fP
561: arguments present in \fIstring\fP. Arguments are split using
562: \fBhistory_tokenize()\fP.
563:
564: .SS History Variables
565:
566: This section describes the externally-visible variables exported by
567: the GNU History Library.
568:
569: .Vb int history_base
570: The logical offset of the first entry in the history list.
571:
572: .Vb int history_length
573: The number of entries currently stored in the history list.
574:
575: .Vb int history_max_entries
576: The maximum number of history entries. This must be changed using
577: \fBstifle_history()\fP.
578:
579: .Vb int history_wite_timestamps
580: If non-zero, timestamps are written to the history file, so they can be
581: preserved between sessions. The default value is 0, meaning that
582: timestamps are not saved.
583: The current timestamp format uses the value of \fIhistory_comment_char\fP
584: to delimit timestamp entries in the history file. If that variable does
585: not have a value (the default), timestamps will not be written.
586:
587: .Vb char history_expansion_char
588: The character that introduces a history event. The default is \fB!\fP.
589: Setting this to 0 inhibits history expansion.
590:
591: .Vb char history_subst_char
592: The character that invokes word substitution if found at the start of
593: a line. The default is \fB^\fP.
594:
595: .Vb char history_comment_char
596: During tokenization, if this character is seen as the first character
597: of a word, then it and all subsequent characters up to a newline are
598: ignored, suppressing history expansion for the remainder of the line.
599: This is disabled by default.
600:
601: .Vb "char *" history_word_delimiters
602: The characters that separate tokens for \fBhistory_tokenize()\fP.
603: The default value is \fB"\ \et\en()<>;&|"\fP.
604:
605: .Vb "char *" history_no_expand_chars
606: The list of characters which inhibit history expansion if found immediately
607: following \fBhistory_expansion_char\fP. The default is space, tab, newline,
608: \fB\er\fP, and \fB=\fP.
609:
610: .Vb "char *" history_search_delimiter_chars
611: The list of additional characters which can delimit a history search
612: string, in addition to space, tab, \fI:\fP and \fI?\fP in the case of
613: a substring search. The default is empty.
614:
615: .Vb int history_quotes_inhibit_expansion
616: If non-zero, single-quoted words are not scanned for the history expansion
617: character. The default value is 0.
618:
619: .Vb "rl_linebuf_func_t *" history_inhibit_expansion_function
620: This should be set to the address of a function that takes two arguments:
621: a \fBchar *\fP (\fIstring\fP)
622: and an \fBint\fP index into that string (\fIi\fP).
623: It should return a non-zero value if the history expansion starting at
624: \fIstring[i]\fP should not be performed; zero if the expansion should
625: be done.
626: It is intended for use by applications like \fBbash\fP that use the history
627: expansion character for additional purposes.
628: By default, this variable is set to \fBNULL\fP.
629: .SH FILES
630: .PD 0
631: .TP
632: .FN ~/.history
633: Default filename for reading and writing saved history
634: .PD
635: .SH "SEE ALSO"
636: .PD 0
637: .TP
638: \fIThe Gnu Readline Library\fP, Brian Fox and Chet Ramey
639: .TP
640: \fIThe Gnu History Library\fP, Brian Fox and Chet Ramey
641: .TP
642: \fIbash\fP(1)
643: .TP
644: \fIreadline\fP(3)
645: .PD
646: .SH AUTHORS
647: Brian Fox, Free Software Foundation
648: .br
649: bfox@gnu.org
650: .PP
651: Chet Ramey, Case Western Reserve University
652: .br
653: chet.ramey@case.edu
654: .SH BUG REPORTS
655: If you find a bug in the
656: .B history
657: library, you should report it. But first, you should
658: make sure that it really is a bug, and that it appears in the latest
659: version of the
660: .B history
661: library that you have.
662: .PP
663: Once you have determined that a bug actually exists, mail a
664: bug report to \fIbug\-readline\fP@\fIgnu.org\fP.
665: If you have a fix, you are welcome to mail that
666: as well! Suggestions and `philosophical' bug reports may be mailed
667: to \fPbug-readline\fP@\fIgnu.org\fP or posted to the Usenet
668: newsgroup
669: .BR gnu.bash.bug .
670: .PP
671: Comments and bug reports concerning
672: this manual page should be directed to
673: .IR chet.ramey@case.edu .
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