1PATCH(P) POSIX Programmer's Manual PATCH(P)
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6 patch - apply changes to files
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9 patch [-blNR][ -c| -e| -n][-d dir][-D define][-i patchfile]
10 [-o outfile][-p num][-r rejectfile][file]
11
13 The patch utility shall read a source (patch) file containing any of
14 the three forms of difference (diff) listings produced by the diff
15 utility (normal, context, or in the style of ed) and apply those dif‐
16 ferences to a file. By default, patch shall read from the standard
17 input.
18 The patch utility shall attempt to determine the type of the diff list‐
20 ing, unless overruled by a -c, -e, or -n option.
21 If the patch file contains more than one patch, patch shall attempt to
23 apply each of them as if they came from separate patch files. (In this
24 case, the application shall ensure that the name of the patch file is
25 determinable for each diff listing.)
26
28 The patch utility shall conform to the Base Definitions volume of
29 IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
30 The following options shall be supported:
32 -b Save a copy of the original contents of each modified file,
34 before the differences are applied, in a file of the same name
35 with the suffix .orig appended to it. If the file already
36 exists, it shall be overwritten; if multiple patches are applied
37 to the same file, the .orig file shall be written only for the
38 first patch. When the -o outfile option is also specified, file
39 .orig shall not be created but, if outfile already exists, out‐
40 file .orig shall be created.
41 -c Interpret the patch file as a context difference (the output of
43 the utility diff when the -c or -C options are specified).
44 -d dir
46 Change the current directory to dir before processing as
47 described in the EXTENDED DESCRIPTION section.
48 -D define
50 Mark changes with one of the following C preprocessor con‐
51 structs:
52 #ifdef define
55 ...
56 #endif
57 #ifndef define
60 ...
61 #endif
62 optionally combined with the C preprocessor construct #else. If the
64 patched file is processed with the C preprocessor, where the macro
65 define is defined, the output shall contain the changes from the patch
66 file; otherwise, the output shall not contain the patches specified in
67 the patch file.
68 -e Interpret the patch file as an ed script, rather than a diff
70 script.
71 -i patchfile
73 Read the patch information from the file named by the pathname
74 patchfile, rather than the standard input.
75 -l (The letter ell.) Cause any sequence of <blank>s in the differ‐
77 ence script to match any sequence of <blank>s in the input file.
78 Other characters shall be matched exactly.
79 -n Interpret the script as a normal difference.
81 -N Ignore patches where the differences have already been applied
83 to the file; by default, already-applied patches shall be
84 rejected.
85 -o outfile
87 Instead of modifying the files (specified by the file operand or
88 the difference listings) directly, write a copy of the file ref‐
89 erenced by each patch, with the appropriate differences applied,
90 to outfile. Multiple patches for a single file shall be applied
91 to the intermediate versions of the file created by any previous
92 patches, and shall result in multiple, concatenated versions of
93 the file being written to outfile.
94 -p num
96 For all pathnames in the patch file that indicate the names of
97 files to be patched, delete num pathname components from the
98 beginning of each pathname. If the pathname in the patch file is
99 absolute, any leading slashes shall be considered the first com‐
100 ponent (that is, -p 1 shall remove the leading slashes). Speci‐
101 fying -p 0 shall cause the full pathname to be used. If -p is
102 not specified, only the basename (the final pathname component)
103 shall be used.
104 -R Reverse the sense of the patch script; that is, assume that the
106 difference script was created from the new version to the old
107 version. The -R option cannot be used with ed scripts. The
108 patch utility shall attempt to reverse each portion of the
109 script before applying it. Rejected differences shall be saved
110 in swapped format. If this option is not specified, and until a
111 portion of the patch file is successfully applied, patch
112 attempts to apply each portion in its reversed sense as well as
113 in its normal sense. If the attempt is successful, the user
114 shall be prompted to determine whether the -R option should be
115 set.
116 -r rejectfile
118 Override the default reject filename. In the default case, the
119 reject file shall have the same name as the output file, with
120 the suffix .rej appended to it; see Patch Application .
121
124 The following operand shall be supported:
125 file A pathname of a file to patch.
127
130 See the INPUT FILES section.
131
133 Input files shall be text files.
134
136 The following environment variables shall affect the execution of
137 patch:
138 LANG Provide a default value for the internationalization variables
140 that are unset or null. (See the Base Definitions volume of
141 IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
142 ables for the precedence of internationalization variables used
143 to determine the values of locale categories.)
144 LC_ALL If set to a non-empty string value, override the values of all
146 the other internationalization variables.
147 LC_CTYPE
149 Determine the locale for the interpretation of sequences of
150 bytes of text data as characters (for example, single-byte as
151 opposed to multi-byte characters in arguments and input files).
152 LC_MESSAGES
154 Determine the locale that should be used to affect the format
155 and contents of diagnostic messages written to standard error
156 and informative messages written to standard output.
157 NLSPATH
159 Determine the location of message catalogs for the processing of
160 LC_MESSAGES .
161 LC_TIME
163 Determine the locale for recognizing the format of file time‐
164 stamps written by the diff utility in a context-difference input
165 file.
166
169 Default.
170
172 Not used.
173
175 The standard error shall be used for diagnostic and informational mes‐
176 sages.
177
179 The output of the patch utility, the save files ( .orig suffixes), and
180 the reject files ( .rej suffixes) shall be text files.
181
183 A patch file may contain patching instructions for more than one file;
184 filenames shall be determined as specified in Filename Determination .
185 When the -b option is specified, for each patched file, the original
186 shall be saved in a file of the same name with the suffix .orig
187 appended to it.
188 For each patched file, a reject file may also be created as noted in
190 Patch Application . In the absence of a -r option, the name of this
191 file shall be formed by appending the suffix .rej to the original file‐
192 name.
193 Patch File Format
195 The patch file shall contain zero or more lines of header information
196 followed by one or more patches. Each patch shall contain zero or more
197 lines of filename identification in the format produced by diff -c, and
198 one or more sets of diff output, which are customarily called hunks.
199 The patch utility shall recognize the following expression in the
201 header information:
202 Index: pathname
204 The file to be patched is named pathname.
206 If all lines (including headers) within a patch begin with the same
209 leading sequence of <blank>s, the patch utility shall remove this
210 sequence before proceeding. Within each patch, if the type of differ‐
211 ence is context, the patch utility shall recognize the following
212 expressions:
213 *** filename timestamp
215 The patches arose from filename.
217 --- filename timestamp
219 The patches should be applied to filename.
221 Each hunk within a patch shall be the diff output to change a line
224 range within the original file. The line numbers for successive hunks
225 within a patch shall occur in ascending order.
226 Filename Determination
228 If no file operand is specified, patch shall perform the following
229 steps to determine the filename to use:
230 1. If the type of diff is context, the patch utility shall delete
232 pathname components (as specified by the -p option) from the file‐
233 name on the line beginning with "***" , then test for the existence
234 of this file relative to the current directory (or the directory
235 specified with the -d option). If the file exists, the patch util‐
236 ity shall use this filename.
237 2. If the type of diff is context, the patch utility shall delete the
239 pathname components (as specified by the -p option) from the file‐
240 name on the line beginning with "---" , then test for the existence
241 of this file relative to the current directory (or the directory
242 specified with the -d option). If the file exists, the patch util‐
243 ity shall use this filename.
244 3. If the header information contains a line beginning with the string
246 Index:, the patch utility shall delete pathname components (as
247 specified by the -p option) from this line, then test for the exis‐
248 tence of this file relative to the current directory (or the direc‐
249 tory specified with the -d option). If the file exists, the patch
250 utility shall use this filename.
251 4. If an SCCS directory exists in the current directory, patch shall
253 attempt to perform a get -e SCCS/s. filename command to retrieve an
254 editable version of the file. If the file exists, the patch utility
255 shall use this filename.
256 5. The patch utility shall write a prompt to standard output and
258 request a filename interactively from the controlling terminal (for
259 example, /dev/tty).
260 Patch Application
262 If the -c, -e, or -n option is present, the patch utility shall inter‐
263 pret information within each hunk as a context difference, an ed dif‐
264 ference, or a normal difference, respectively. In the absence of any of
265 these options, the patch utility shall determine the type of difference
266 based on the format of information within the hunk.
267 For each hunk, the patch utility shall begin to search for the place to
269 apply the patch at the line number at the beginning of the hunk, plus
270 or minus any offset used in applying the previous hunk. If lines match‐
271 ing the hunk context are not found, patch shall scan both forwards and
272 backwards at least 1000 bytes for a set of lines that match the hunk
273 context.
274 If no such place is found and it is a context difference, then another
276 scan shall take place, ignoring the first and last line of context. If
277 that fails, the first two and last two lines of context shall be
278 ignored and another scan shall be made. Implementations may search
279 more extensively for installation locations.
280 If no location can be found, the patch utility shall append the hunk to
282 the reject file. The rejected hunk shall be written in context-differ‐
283 ence format regardless of the format of the patch file. If the input
284 was a normal or ed-style difference, the reject file may contain dif‐
285 ferences with zero lines of context. The line numbers on the hunks in
286 the reject file may be different from the line numbers in the patch
287 file since they shall reflect the approximate locations for the failed
288 hunks in the new file rather than the old one.
289 If the type of patch is an ed diff, the implementation may accomplish
291 the patching by invoking the ed utility.
292
294 The following exit values shall be returned:
295 0 Successful completion.
297 1 One or more lines were written to a reject file.
299 >1 An error occurred.
301
304 Patches that cannot be correctly placed in the file shall be written to
305 a reject file.
306 The following sections are informative.
308
310 The -R option does not work with ed scripts because there is too little
311 information to reconstruct the reverse operation.
312 The -p option makes it possible to customize a patch file to local user
314 directory structures without manually editing the patch file. For exam‐
315 ple, if the filename in the patch file was:
316 /curds/whey/src/blurfl/blurfl.c
319 Setting -p 0 gives the entire pathname unmodified; -p 1 gives:
321 curds/whey/src/blurfl/blurfl.c
324 without the leading slash, -p 4 gives:
326 blurfl/blurfl.c
329 and not specifying -p at all gives:
331 blurfl.c .
334
336 None.
337
339 Some of the functionality in historical patch implementations was not
340 specified. The following documents those features present in historical
341 implementations that have not been specified.
342 A deleted piece of functionality was the '+' pseudo-option allowing an
344 additional set of options and a patch file operand to be given. This
345 was seen as being insufficiently useful to standardize.
346 In historical implementations, if the string "Prereq:" appeared in the
348 header, the patch utility would search for the corresponding version
349 information (the string specified in the header, delimited by <blank>s
350 or the beginning or end of a line or the file) anywhere in the original
351 file. This was deleted as too simplistic and insufficiently trustworthy
352 a mechanism to standardize. For example, if:
353 Prereq: 1.2
356 were in the header, the presence of a delimited 1.2 anywhere in the
358 file would satisfy the prerequisite.
359 The following options were dropped from historical implementations of
361 patch as insufficiently useful to standardize:
362 -b The -b option historically provided a method for changing the
364 name extension of the backup file from the default .orig. This
365 option has been modified and retained in this volume of
366 IEEE Std 1003.1-2001.
367 -F The -F option specified the number of lines of a context diff to
369 ignore when searching for a place to install a patch.
370 -f The -f option historically caused patch not to request addi‐
372 tional information from the user.
373 -r The -r option historically provided a method of overriding the
375 extension of the reject file from the default .rej.
376 -s The -s option historically caused patch to work silently unless
378 an error occurred.
379 -x The -x option historically set internal debugging flags.
381 In some file system implementations, the saving of a .orig file may
384 produce unwanted results. In the case of 12, 13, or 14-character file‐
385 names (on file systems supporting 14-character maximum filenames), the
386 .orig file overwrites the new file. The reject file may also exceed
387 this filename limit. It was suggested, due to some historical practice,
388 that a tilde ( '~' ) suffix be used instead of .orig and some other
389 character instead of the .rej suffix. This was rejected because it is
390 not obvious to the user which file is which. The suffixes .orig and
391 .rej are clearer and more understandable.
392 The -b option has the opposite sense in some historical implementa‐
394 tions-do not save the .orig file. The default case here is not to save
395 the files, making patch behave more consistently with the other stan‐
396 dard utilities.
397 The -w option in early proposals was changed to -l to match historical
399 practice.
400 The -N option was included because without it, a non-interactive appli‐
402 cation cannot reject previously applied patches. For example, if a
403 user is piping the output of diff into the patch utility, and the user
404 only wants to patch a file to a newer version non-interactively, the -N
405 option is required.
406 Changes to the -l option description were proposed to allow matching
408 across <newline>s in addition to just <blank>s. Since this is not his‐
409 torical practice, and since some ambiguities could result, it is sug‐
410 gested that future developments in this area utilize another option
411 letter, such as -L.
412
414 None.
415
417 ed , diff
418
420 Portions of this text are reprinted and reproduced in electronic form
421 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
422 -- Portable Operating System Interface (POSIX), The Open Group Base
423 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
424 Electrical and Electronics Engineers, Inc and The Open Group. In the
425 event of any discrepancy between this version and the original IEEE and
426 The Open Group Standard, the original IEEE and The Open Group Standard
427 is the referee document. The original Standard can be obtained online
428 at http://www.opengroup.org/unix/online.html .
429IEEE/The Open Group 2003 PATCH(P)