Options may start with '+' (enable) or '-' (disable),
folowed by a letter whose case isn't significant.
The option letter may be followed by a parameter,
whose case usually is significant.
For options that have no enable/disable concept,
you may use either '-' or '+'.
-x<N>
+x<N>
Description of x option. Default: -x.
ENVIRONMENT
XXX uses a few environment variables.
B_XXX
This is the border width around XXX's widgets.
The default is 3 pixels.
D_XXX<N><file>
This is a debug level (a single digit) plus an optional output file name.
The debug level controls how much information
XXX writes to the output file.
The default is 1, which produces only fatal error messages.
If the file is omitted, stderr is used.