Sanity checking of files

[verdurin]

As it stands, an error in the specification of command-line parameters could lead to silent overwriting of an existing file. Not that I would ever make that sort of mistake myself...

[larsks]

Thanks for the comment. Are you suggesting that in general trying to overwrite an existing file should result in an error (and maybe adding a --force flag to avoid that behavior)? I would be happy to accept pull requests for that feature.