Feature request: -O, --output-mode: specify clobber, noclobber, or append for output files

[XLTechie]

There is a -o switch, to specify an output file. However, there is no info in the readme/help, about what it does if the file already exists.

There are many possible ways to go. One potential one is:

• --output-mode=noclobber (default): Don't overwrite if file exists
• --output-mode=clobber: Truncate and replace existing output file.
• --output-mode=append: Add to an existing output file.

The last is the option I need right now, which made me think of this. Yes, I know about >> shell redirection for append, but not everyone does, and that isn't practical in all scripting/piping scenarios.