Option conventions
==================
To provide a clean and consistent behavior, we chose to have all these
programs use the GNU function `getopt_long_only' to parse command lines.
As a result, you can:
* give the options in any order, interspersed as you wish with
non-option arguments;
* use `-' or `--' to start an option name;
* use any unambiguous abbreviation for an option name;
* separate option names and values with either `=' or one or more
spaces;
* use filenames that would otherwise look like options by putting
them after an option `--'.
By convention, non-option arguments, if specified, generally define
the name of an input file, as documented for each program.
If a particular option with a value is given more than once, it is the
last value that counts.
For example, the following command line specifies the options `foo',
`bar', and `verbose'; gives the value `baz' to the `abc' option, and
the value `xyz' to the `quux' option; and specifies the filename
`-myfile-'.
-foo --bar -verb -abc=baz -quux karl --quux xyz -- -myfile-