Where the commands or options are defined ("4.1.2 Commands to select […]"), it should also be noted, whether a file should be written on the command-line or not. E.g. "-e [FILE]" instead of only "-e". It should also be considered,whether a synopsis should be written or whether there are too many commands for it.
In the texinfo document, which is opened, when invoking 'info gnupg', there is a subchapter called "Invoking GPG". In this chapter, commands and options are defined. This is the text I mean.
yes. that's why i wrote it in '['-brackets.
but usually, in info-documents a synopsis is written about it.
I think that it's not self-evident, that "you can either give a file or let the tool read from stdin or output to stdout" and therefore should be written explicitly.