PATCH(1)                                                 PATCH(1)

     NAME
          patch - apply patches

     SYNOPSIS
          patch [ -R ] [ -p nstrip ] [ patch ... ]

     DESCRIPTION
          Patch scans its input for a sequence of patches, and applies
          them, printing the list of changed files.  When an applied
          patch does not match precisely, patch will scan the input
          file for matching context, applying the patch up to 250
          lines away from its original location.  If a hunk does not
          apply, then the file is left untouched.

          The following options are supported:

          -R   Reverse direction of the patch. Additions become
               removals, and the new and old file names are swapped.

          -n   Print the files that would be modified by this patch,
               but do not apply it.

          -p nstrip
               Remove the prefix containing nstrip leading slashes
               from each file path in the diff file.

     INPUT FORMAT
          A patch begins with a patch header, and is followed by a
          sequence of one or more hunks.  All lines before a patch
          header or after the last hunk of a patch are comments, and
          are ignored by patch. A patch header is a sequence of 2
          lines in the following format:

               --- oldfile [trailing text]
               +++ newfile [trailing text]

          A hunk must immediately follow a patch header or another
          hunk.  It begins with a header line in the following format:

               @@ -count,addr +count,addr @@

          And contains a sequence of lines beginning with a `-', `+',
          or space characters.  A `-' indicates that the line is to be
          removed from the old file.  A `+' indicates that the line is
          to be inserted into the new file.  A space indicates that
          the line is context.  It will be copied unchanged from the
          old file to the new file.

          If the old file is `/dev/null', the patch indicates a file
          creation.  If the new file is `/dev/null', the patch

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     PATCH(1)                                                 PATCH(1)

          indicates a file deletion.  In this case, the file printed
          is the file being removed.

     SEE ALSO
          diff(1), git/export(1)

     BUGS
          The output of diff -c is not handled.

          Reject files and backups are not supported.

          All files are processed in memory, limiting the maximum file
          size to available RAM.

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