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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 |
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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.1‐2017, 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.1‐2017, 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.1‐2017.
-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.1‐2017, Chapter 8,
Environment Variables, Section 12.2, Utility Syntax Guidelines
Portions of this text are reprinted and reproduced in electronic
form from IEEE Std 1003.1-2017, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The
Open Group Base Specifications Issue 7, 2018 Edition, Copyright
(C) 2018 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. 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.opengroup.org/unix/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 2017 PATCH(1P)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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