10.6 Multiple Patches in a File

If the patch file contains more than one patch, and if you do not specify an input file on the command line, patch tries to apply each patch as if they came from separate patch files. This means that it determines the name of the file to patch for each patch, and that it examines the leading text before each patch for file names and prerequisite revision level (see section Tips for Making and Using Patches, for more on that topic).

patch uses the following rules to intuit a file name from the leading text before a patch. First, patch takes an ordered list of candidate file names as follows:

• If the header is that of a context diff, patch takes the old and new file names in the header. A name is ignored if it does not have enough slashes to satisfy the ‘-pnum’ or ‘--strip=num’ option. The name ‘/dev/null’ is also ignored.
• If there is an ‘Index:’ line in the leading garbage and if either the old and new names are both absent or if patch is conforming to POSIX, patch takes the name in the ‘Index:’ line.
• For the purpose of the following rules, the candidate file names are considered to be in the order (old, new, index), regardless of the order that they appear in the header.

Then patch selects a file name from the candidate list as follows:

• If some of the named files exist, patch selects the first name if conforming to POSIX, and the best name otherwise.
• If patch is not ignoring RCS, ClearCase, and SCCS (see section Revision Control), and no named files exist but an RCS, ClearCase, or SCCS master is found, patch selects the first named file with an RCS, ClearCase, or SCCS master.
• If no named files exist, no RCS, ClearCase, or SCCS master was found, some names are given, patch is not conforming to POSIX, and the patch appears to create a file, patch selects the best name requiring the creation of the fewest directories.
• If no file name results from the above heuristics, you are asked for the name of the file to patch, and patch selects that name.

To determine the best of a nonempty list of file names, patch first takes all the names with the fewest path name components; of those, it then takes all the names with the shortest basename; of those, it then takes all the shortest names; finally, it takes the first remaining name.

See section patch and the POSIX Standard, to see whether patch is conforming to POSIX.