Minimal filename completions for the unimplemented subcommands

[cgjosephlee]

For tools like bedtools, there are too many subcommands and not everyone is implemented for completion. Also most of them are not frequently used and maybe change by time.

Can we have a minimal filename completes when a subcommand is not defined or newly added? Just like default behavior without completion script.

e.g. bedtools maskfasta and samtools fastq

[kloetzl]

Is there a way to do both? Print a warning and file completion at the same time?

[cgjosephlee]

https://github.com/kloetzl/biozsh/blob/master/completions/_samtools#L271-L273
Maybe be add _arguments '*:files:_files' here?
It works like

But I'm not sure if this is a clever way to do this.