diffutils d.8.1 cmp: some useful options undocumented

[D. Hugh Redelmeier]

cmp(1) and info cmp have the same content.  Neither document these flags
that are handled according to long_options in the source

    99    {"print-bytes", 0, 0, 'b'},
   100    {"print-chars", 0, 0, 'c'}, /* obsolescent as of diffutils 2.7.3 */
   101    {"ignore-initial", 1, 0, 'i'},
   102    {"verbose", 0, 0, 'l'},
   103    {"bytes", 1, 0, 'n'},
   104    {"silent", 0, 0, 's'},
   105    {"quiet", 0, 0, 's'},
   106    {"version", 0, 0, 'v'},
   107    {"help", 0, 0, HELP_OPTION},

(-l and -s are documented, but not their long forms.)

I took a stab at documenting these flags, but I found that --help had
done a reasonable job.  I think that this information should be
incorporated into cmp(1) and info cmp:

    Usage: cmp [OPTION]... FILE1 [FILE2 [SKIP1 [SKIP2]]]
    Compare two files byte by byte.

      -b  --print-bytes  Print differing bytes.
      -i SKIP  --ignore-initial=SKIP  Skip the first SKIP bytes of input.
      -i SKIP1:SKIP2  --ignore-initial=SKIP1:SKIP2
        Skip the first SKIP1 bytes of FILE1 and the first SKIP2 bytes of FILE2.
      -l  --verbose  Output byte numbers and values of all differing bytes.
      -n LIMIT  --bytes=LIMIT  Compare at most LIMIT bytes.
      -s  --quiet  --silent  Output nothing; yield exit status only.
      -v  --version  Output version info.
      --help  Output this help.

    SKIP1 and SKIP2 are the number of bytes to skip in each file.
    SKIP values may be followed by the following multiplicative suffixes:
    kB 1000, K 1024, MB 1,000,000, M 1,048,576,
    GB 1,000,000,000, G 1,073,741,824, and so on for T, P, E, Z, Y.

    If a FILE is `-' or missing, read standard input.

    Report bugs to <address@hidden>.