patch(1) User Commands patch(1)
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 command reads a source (patch) file containing any of the
three forms of difference (diff) listings produced by the diff(1) com-
mand (normal, context or in the style of ed(1)) and apply those differ-
ences to a file. By default, patch reads from the standard input.
patch attempts to determine the type of the diff listing, unless over-
ruled by a -c, -e, or -n option.
If the patch file contains more than one patch, patch will attempt to
apply each of them as if they came from separate patch files. (In this
case the name of the patch file must be determinable for each diff
The following options are supported:
-b Saves 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 will be overwritten. If
multiple patches are applied to the same file, the
.orig file will be written only for the first patch.
When the -o outfile option is also specified, file.orig
will not be created but, if outfile already exists,
outfile.orig will be created.
-c Interprets the patch file as a context difference (the
output of the command diff when the -c or -C options
-d dir Changes the current directory to dir before processing
as described in EXTENDED DESCRIPTION.
-D define Marks changes with the C preprocessor construct:
The option-argument define will be used as the differentiating symbol.
-e Interprets the patch file as an ed script, rather than
a diff script.
-i patchfile Reads the patch information from the file named by the
path name patchfile, rather than the standard input.
-l (The letter ell.) Causes any sequence of blank charac-
ters in the difference script to match any sequence of
blank characters in the input file. Other characters
will be matched exactly.
-n Interprets the script as a normal difference.
-N Ignores patches where the differences have already been
applied to the file; by default, already-applied
patches are rejected.
-o outfile Instead of modifying the files (specified by the file
operand or the difference listings) directly, writes a
copy of the file referenced by each patch, with the
appropriate differences applied, to outfile. Multiple
patches for a single file will be applied to the inter-
mediate versions of the file created by any previous
patches, and will result in multiple, concatenated ver-
sions of the file being written to outfile.
-p num For all path names in the patch file that indicate the
names of files to be patched, deletes num path name
components from the beginning of each path name. If the
path name in the patch file is absolute, any leading
slashes are considered the first component (that is, -p
1 removes the leading slashes). Specifying -p 0 causes
the full path name to be used. If -p is not specified,
only the basename (the final path name component) is
-R Reverses the sense of the patch script. That is,
assumes that the difference script was created from the
new version to the old version. The -R option cannot be
used with ed scripts. patch attempts to reverse each
portion of the script before applying it. Rejected dif-
ferences will 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 will be prompted to determine if the -R option
should be set.
-r rejectfile Overrides the default reject file name. In the default
case, the reject file will have the same name as the
output file, with the suffix .rej appended to it. See
-u Interprets the patch file as a unified context differ-
ence, that is, the output of the command diff when the
-u or -U options are specified.
The following operand is supported:
file A path name of a file to patch.
The -R option will 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 exam-
ple, if the file name in the patch file was
o Setting -p 0 gives the entire path name unmodified.
o Setting -p 1 gives:
o Without the leading slash, -p 4 gives:
o Not specifying -p at all gives:
When using -b in some file system implementations, the saving of a
.orig file may produce unwanted results. In the case of 12-, 13-, or
14-character file names, on file systems supporting 14-character maxi-
mum file names, the .orig file will overwrite the new file.
See environ(5) for descriptions of the following environment variables
that affect the execution of patch: LANG, LC_ALL, LC_CTYPE, LC_MES-
SAGES, LC_TIME, and NLSPATH.
The output of patch the save files (.orig suffixes) and the reject
files (.rej suffixes) will be text files.
A patch file may contain patching instructions for more than one file.
File names are determined as specified in Patch Determination. When the
-b option is specified, for each patched file, the original will 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 an -r option, the name of this
file will be formed by appending the suffix .rej to the original file
Patch File Format
The patch file must contain zero or more lines of header information
followed by one or more patches. Each patch must contain zero or more
lines of file name identification in the format produced by diff -c,
and one or more sets of diff output, which are customarily called
patch recognizes 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, patch will remove this sequence
before proceeding. Within each patch, if the type of difference is con-
text, patch recognizes the following expressions:
*** filename timestamp
The patches arose from filename.
--- filename timestamp
The patches should be applied to filename.
Each hunk within a patch must be the diff output to change a line range
within the original file. The line numbers for successive hunks within
a patch must occur in ascending order.
File Name Determination
If no file operand is specified, patch performs the following steps to
obtain a path name:
1. If the patch contains the strings *** and ---, patch strips compo-
nents from the beginning of each path name (depending on the pres-
ence or value of the -p option), then tests for the existence of
both files in the current directory (or directory specified with
the -d option).
2. If both files exist, patch assumes that no path name can be
obtained from this step. If the header information contains a line
with the string Index:, patch strips components from the beginning
of the path name (depending on -p), then tests for the existence of
this file in the current directory (or directory specified with the
3. If an SCCS directory exists in the current directory, patch will
attempt to perform a get -e SCCS/s.filename command to retrieve an
editable version of the file.
4. If no path name can be obtained by applying the previous steps, or
if the path names obtained do not exist, patch will write a prompt
to standard output and request a file name interactively from stan-
If the -c, -e, -n, or -u option is present, patch will interpret infor-
mation within each hunk as a context difference, an ed difference, a
normal difference, or a unified context difference, respectively. In
the absence of any of these options, patch determines the type of dif-
ference based on the format of information within the hunk.
For each hunk, patch begins to search for the place to apply the patch
at the line number at the beginning of the hunk, plus or minus any off-
set used in applying the previous hunk. If lines matching the hunk con-
text are not found, patch scans 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 will take place, ignoring the first and last line of context. If
that fails, the first two and last two lines of context will be ignored
and another scan will be made. Implementations may search more exten-
sively for installation locations.
If no location can be found, patch will append the hunk to the reject
file. The rejected hunk will be written in context-difference format
regardless of the format of the patch file. 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
will 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 command.
The following exit values are returned:
0 Successful completion.
1 One or more lines were written to a reject file.
>>1 An error occurred.
See attributes(5) for descriptions of the following attributes:
tab() allbox; cw(2.750000i)| cw(2.750000i) lw(2.750000i)|
lw(2.750000i). ATTRIBUTE TYPEATTRIBUTE VALUE AvailabilitySUNWcsu
ed(1), diff(1), attributes(5), environ(5), standards(5)
SunOS 5.10 28 Sep 2001 patch(1)