patch -p0

-pnum or --strip=num

Strip the smallest prefix containing num leading slashes from each file name found in the patch file. A sequence of one or more adjacent slashes is counted as a single slash. This controls how file names found in the patch file are treated, in case you keep your files in a different directory than the person who sent out the patch. For example, supposing the file name in the patch file was


    /u/howard/src/blurfl/blurfl.c



setting -p0 gives the entire file name unmodified, -p1 gives

    u/howard/src/blurfl/blurfl.c



without the leading slash, -p4 gives

    blurfl/blurfl.c



and not specifying -p at all just gives you blurfl.c. Whatever you end up with is looked for either in the current directory, or the directory specified by the -d option.