Beside the space issue, you also might take care about globbing.
If you e.g. "cp *" you won't copy hidden files of the directory, but all
inside folders of the directory. If you e.g. "rm *", you'll delete all
files, including hidden files.
Regarding to the mail addresses I suspect you're using braille. Anybody
using a monitor, who isn't aware of some basic rules, could use GUIs
instead of a terminal.
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