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PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
PATCH(1P) POSIX Programmer's Manual PATCH(1P)
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
patch — apply changes to files
patch [−blNR] [−c|−e|−n|−u] [−d dir] [−D define] [−i patchfile]
[−o outfile] [−p num] [−r rejectfile] [file]
The patch utility shall read a source (patch) file containing any of
four forms of difference (diff) listings produced by the diff utility
(normal, copied context, unified context, or in the style of ed) and
apply those differences to a file. By default, patch shall read from
the standard input.
The patch utility shall attempt to determine the type of the diff
listing, unless overruled by a −c, −e, −n, or −u option.
If the patch file contains more than one patch, patch shall attempt
to apply each of them as if they came from separate patch files. (In
this case, the application shall ensure that the name of the patch
file is determinable for each diff listing.)
The patch utility shall conform to the Base Definitions volume of
POSIX.1‐2008, Section 12.2, Utility Syntax Guidelines.
The following options shall be supported:
−b Save a copy of the original contents of each modified file,
before the differences are applied, in a file of the same
name with the suffix .orig appended to it. If the file
already exists, it shall be overwritten; if multiple
patches are applied to the same file, the .orig file shall
be written only for the first patch. When the −o outfile
option is also specified, file.orig shall not be created
but, if outfile already exists, outfile.orig shall be
created.
−c Interpret the patch file as a copied context difference
(the output of the utility diff when the −c or −C options
are specified).
−d dir Change the current directory to dir before processing as
described in the EXTENDED DESCRIPTION section.
−D define Mark changes with one of the following C preprocessor
constructs:
#ifdef define
...
#endif
#ifndef define
...
#endif
optionally combined with the C preprocessor construct
#else. If the patched file is processed with the C
preprocessor, where the macro define is defined, the output
shall contain the changes from the patch file; otherwise,
the output shall not contain the patches specified in the
patch file.
−e Interpret the patch file as an ed script, rather than a
diff script.
−i patchfile
Read the patch information from the file named by the
pathname patchfile, rather than the standard input.
−l (The letter ell.) Cause any sequence of <blank> characters
in the difference script to match any sequence of <blank>
characters in the input file. Other characters shall be
matched exactly.
−n Interpret the script as a normal difference.
−N Ignore patches where the differences have already been
applied to the file; by default, already-applied patches
shall be rejected.
−o outfile
Instead of modifying the files (specified by the file
operand or the difference listings) directly, write a copy
of the file referenced by each patch, with the appropriate
differences applied, to outfile. Multiple patches for a
single file shall be applied to the intermediate versions
of the file created by any previous patches, and shall
result in multiple, concatenated versions of the file being
written to outfile.
−p num For all pathnames in the patch file that indicate the names
of files to be patched, delete num pathname components from
the beginning of each pathname. If the pathname in the
patch file is absolute, any leading <slash> characters
shall be considered the first component (that is, −p 1
shall remove the leading <slash> characters). Specifying
−p 0 shall cause the full pathname to be used. If −p is not
specified, only the basename (the final pathname component)
shall be used.
−R Reverse the sense of the patch script; that is, assume that
the difference script was created from the new version to
the old version. The −R option cannot be used with ed
scripts. The patch utility shall attempt to reverse each
portion of the script before applying it. Rejected
differences shall be saved in swapped format. If this
option is not specified, and until a portion of the patch
file is successfully applied, patch attempts to apply each
portion in its reversed sense as well as in its normal
sense. If the attempt is successful, the user shall be
prompted to determine whether the −R option should be set.
−r rejectfile
Override the default reject filename. In the default case,
the reject file shall have the same name as the output
file, with the suffix .rej appended to it; see Patch
Application.
−u Interpret the patch file as a unified context difference
(the output of the diff utility when the −u or −U options
are specified).
The following operand shall be supported:
file A pathname of a file to patch.
See the INPUT FILES section.
Input files shall be text files.
The following environment variables shall affect the execution of
patch:
LANG Provide a default value for the internationalization
variables that are unset or null. (See the Base Definitions
volume of POSIX.1‐2008, Section 8.2, Internationalization
Variables the precedence of internationalization variables
used to determine the values of locale categories.)
LC_ALL If set to a non-empty string value, override the values of
all the other internationalization variables.
LC_COLLATE
Determine the locale for the behavior of ranges,
equivalence classes, and multi-character collating elements
used in the extended regular expression defined for the
yesexpr locale keyword in the LC_MESSAGES category.
LC_CTYPE Determine the locale for the interpretation of sequences of
bytes of text data as characters (for example, single-byte
as opposed to multi-byte characters in arguments and input
files), and the behavior of character classes used in the
extended regular expression defined for the yesexpr locale
keyword in the LC_MESSAGES category.
LC_MESSAGES
Determine the locale used to process affirmative responses,
and the locale used to affect the format and contents of
diagnostic messages and prompts written to standard error.
NLSPATH Determine the location of message catalogs for the
processing of LC_MESSAGES.
LC_TIME Determine the locale for recognizing the format of file
timestamps written by the diff utility in a context-
difference input file.
Default.
Not used.
The standard error shall be used for diagnostic and informational
messages.
The output of the patch utility, the save files (.orig suffixes), and
the reject files (.rej suffixes) shall be text files.
A patch file may contain patching instructions for more than one
file; filenames shall be determined as specified in Filename
Determination. When the −b option is specified, for each patched
file, the original shall be saved in a file of the same name with the
suffix .orig appended to it.
For each patched file, a reject file may also be created as noted in
Patch Application. In the absence of a −r option, the name of this
file shall be formed by appending the suffix .rej to the original
filename.
Patch File Format
The patch file shall contain zero or more lines of header information
followed by one or more patches. Each patch shall contain zero or
more lines of filename identification in the format produced by the
−c, −C, −u, or −U options of the diff utility, and one or more sets
of diff output, which are customarily called hunks.
The patch utility shall recognize the following expression in the
header information:
Index: pathname
The file to be patched is named pathname.
If all lines (including headers) within a patch begin with the same
leading sequence of <blank> characters, the patch utility shall
remove this sequence before proceeding. Within each patch, if the
type of difference is common context, the patch utility shall
recognize the following expressions:
*** filename timestamp
The patches arose from filename.
−−− filename timestamp
The patches should be applied to filename.
If the type of difference is unified context, the patch utility shall
recognize the following expressions:
−−− filename timestamp
The patches arose from filename.
+++ filename timestamp
The patches should be applied to filename.
Each hunk within a patch shall be the diff output to change a line
range within the original file. The line numbers for successive hunks
within a patch shall occur in ascending order.
Filename Determination
If no file operand is specified, patch shall perform the following
steps to determine the filename to use:
1. If the type of diff is context, the patch utility shall delete
pathname components (as specified by the −p option) from the
filename on the line beginning with "***" (if copied context) or
"−−−" (if unified context), then test for the existence of this
file relative to the current directory (or the directory
specified with the −d option). If the file exists, the patch
utility shall use this filename.
2. If the type of diff is context, the patch utility shall delete
the pathname components (as specified by the −p option) from the
filename on the line beginning with "−−−" (if copied context) or
"+++" (if unified context), then test for the existence of this
file relative to the current directory (or the directory
specified with the −d option). If the file exists, the patch
utility shall use this filename.
3. If the header information contains a line beginning with the
string Index:, the patch utility shall delete pathname components
(as specified by the −p option) from this line, then test for the
existence of this file relative to the current directory (or the
directory specified with the −d option). If the file exists, the
patch utility shall use this filename.
4. If an SCCS directory exists in the current directory, patch shall
attempt to perform a get −e SCCS/s.filename command to retrieve
an editable version of the file. If the file exists, the patch
utility shall use this filename.
5. The patch utility shall write a prompt to standard output and
request a filename interactively from the controlling terminal
(for example, /dev/tty).
Patch Application
If the −c, −e, −n, or −u option is present, the patch utility shall
interpret information within each hunk as a copied context
difference, an ed difference, a normal difference, or a unified
context difference, respectively. In the absence of any of these
options, the patch utility shall determine the type of difference
based on the format of information within the hunk.
For each hunk, the patch utility shall begin to search for the place
to apply the patch at the line number at the beginning of the hunk,
plus or minus any offset used in applying the previous hunk. If lines
matching the hunk context are not found, patch shall scan both
forwards and backwards at least 1000 bytes for a set of lines that
match the hunk context.
If no such place is found and it is a context difference, then
another scan shall take place, ignoring the first and last line of
context. If that fails, the first two and last two lines of context
shall be ignored and another scan shall be made. Implementations may
search more extensively for installation locations.
If no location can be found, the patch utility shall append the hunk
to the reject file. A rejected hunk that is a copied context
difference, an ed difference, or a normal difference shall be written
in copied-context-difference format regardless of the format of the
patch file. It is implementation-defined whether a rejected hunk that
is a unified context difference is written in copied-context-
difference format or in unified-context-difference format. If the
input was a normal or ed-style difference, the reject file may
contain differences with zero lines of context. The line numbers on
the hunks in the reject file may be different from the line numbers
in the patch file since they shall reflect the approximate locations
for the failed hunks in the new file rather than the old one.
If the type of patch is an ed diff, the implementation may accomplish
the patching by invoking the ed utility.
The following exit values shall be returned:
0 Successful completion.
1 One or more lines were written to a reject file.
>1 An error occurred.
Patches that cannot be correctly placed in the file shall be written
to a reject file.
The following sections are informative.
The −R option does not work with ed scripts because there is too
little information to reconstruct the reverse operation.
The −p option makes it possible to customize a patch file to local
user directory structures without manually editing the patch file.
For example, if the filename in the patch file was:
/curds/whey/src/blurfl/blurfl.c
Setting −p 0 gives the entire pathname unmodified; −p 1 gives:
curds/whey/src/blurfl/blurfl.c
without the leading <slash>, −p 4 gives:
blurfl/blurfl.c
and not specifying −p at all gives:
blurfl.c .
None.
Some of the functionality in historical patch implementations was not
specified. The following documents those features present in
historical implementations that have not been specified.
A deleted piece of functionality was the '+' pseudo-option allowing
an additional set of options and a patch file operand to be given.
This was seen as being insufficiently useful to standardize.
In historical implementations, if the string "Prereq:" appeared in
the header, the patch utility would search for the corresponding
version information (the string specified in the header, delimited by
<blank> characters or the beginning or end of a line or the file)
anywhere in the original file. This was deleted as too simplistic and
insufficiently trustworthy a mechanism to standardize. For example,
if:
Prereq: 1.2
were in the header, the presence of a delimited 1.2 anywhere in the
file would satisfy the prerequisite.
The following options were dropped from historical implementations of
patch as insufficiently useful to standardize:
−b The −b option historically provided a method for changing
the name extension of the backup file from the default
.orig. This option has been modified and retained in this
volume of POSIX.1‐2008.
−F The −F option specified the number of lines of a context
diff to ignore when searching for a place to install a
patch.
−f The −f option historically caused patch not to request
additional information from the user.
−r The −r option historically provided a method of overriding
the extension of the reject file from the default .rej.
−s The −s option historically caused patch to work silently
unless an error occurred.
−x The −x option historically set internal debugging flags.
In some file system implementations, the saving of a .orig file may
produce unwanted results. In the case of 12, 13, or 14-character
filenames (on file systems supporting 14-character maximum
filenames), the .orig file overwrites the new file. The reject file
may also exceed this filename limit. It was suggested, due to some
historical practice, that a <tilde> ('~') suffix be used instead of
.orig and some other character instead of the .rej suffix. This was
rejected because it is not obvious to the user which file is which.
The suffixes .orig and .rej are clearer and more understandable.
The −b option has the opposite sense in some historical
implementations—do not save the .orig file. The default case here is
not to save the files, making patch behave more consistently with the
other standard utilities.
The −w option in early proposals was changed to −l to match
historical practice.
The −N option was included because without it, a non-interactive
application cannot reject previously applied patches. For example, if
a user is piping the output of diff into the patch utility, and the
user only wants to patch a file to a newer version non-interactively,
the −N option is required.
Changes to the −l option description were proposed to allow matching
across <newline> characters in addition to just <blank> characters.
Since this is not historical practice, and since some ambiguities
could result, it is suggested that future developments in this area
utilize another option letter, such as −L.
The −u option of GNU patch has been added, along with support for
unified context formats.
None.
diff(1p), ed(1p)
The Base Definitions volume of POSIX.1‐2008, Chapter 8, Environment
Variables, Section 12.2, Utility Syntax Guidelines
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) In the event of any discrepancy between this version and
the original IEEE and The Open Group Standard, the original IEEE and
The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 PATCH(1P)