patch(1)							   User Commands							  patch(1)

NAME

       patch - apply changes to files

SYNOPSIS

       patch [-blNR] [-c | -e | -n | -u]  [-d dir] [-D define] [-i patchfile] [-o outfile] [-p num] [-r rejectfile] [file]

DESCRIPTION

       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 differences to a file.  By default, patch reads from the standard input.

       patch attempts to determine the type of the diff listing, unless overruled 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 listing.)

OPTIONS

       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 are specified).

       -d dir	       Changes the current directory to dir before processing as described in EXTENDED DESCRIPTION.

       -D define       Marks changes with the C preprocessor construct:

		       #ifdef define
		       ...
		       #endif

       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 characters in the difference script to match any sequence of  blank  charac-
		       ters 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 intermediate versions of the file created by any previous patches, and will result in multiple, con-
		       catenated versions 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 used.

       -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 differences 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 Patch Application.

       -u	       Interprets  the	patch  file  as  a  unified  context difference, that is, the output of the command diff when the -u or -U
		       options are specified.

OPERANDS

       The following operand is supported:

       file	A path name of a file to patch.

USAGE

       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
       example, if the file name in the patch file was /curds/whey/src/blurfl/blurfl.c:

	 o  Setting -p 0 gives the entire path name unmodified.

	 o  Setting -p 1 gives:

	    curds/whey/src/blurfl/blurfl.c

	 o  Without the leading slash, -p 4 gives:

	    blurfl/blurfl.c

	 o  Not specifying -p at all gives:

	    blurfl.c

       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 maximum file names, the .orig file will overwrite the new file.

ENVIRONMENT VARIABLES

       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.

OUTPUT FILES

       The output of patch the save files (.orig suffixes) and the reject files (.rej suffixes) will be text files.

EXTENDED DESCRIPTION

       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 name.

   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
       hunks.

       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 context, 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 components from the beginning of each path name (depending on the  presence
	   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 -d option).

       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 standard input.

   Patch Application
       If the -c, -e, -n, or -u option is present, patch will interpret information 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
       offset  used  in  applying  the previous hunk. If lines matching the hunk context 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
       extensively 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.

EXIT STATUS

       The following exit values are returned:

       0	Successful completion.

       1	One or more lines were written to a reject file.

       >1	An error occurred.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       ed(1), diff(1), attributes(5), environ(5), standards(5)

SunOS 5.10							    28 Sep 2001 							  patch(1)