Thank you for the patch -- this makes sense. I'm not fond of the name
'args-from-files' though. How about this behaviour: if the supplied
strings for KEY and/or OTP contain '/' or '\' the strings are treated as
names of files to be read, instead of data strings? And if the string
is '-' stdin is used.
'@filename' would be somewhat common, I think. Taking a slash to mean a filename also seems sensible, at least as long as you don't take base64 input too. But why backslash? Some might also like to be able to pass an fd number, to support piping. E.g. the '*-fd' options to gpg.