Originally Posted by fratermus
For onlookers: quoting the space-containing string or \backslash-escaping the space will allow users to interact with space-containing files and dirs. Some shells make this with filename completion.
If the user (or the utility) is aware of the requirement.
Any character, except the one having a byte value representation of 0 (zero) may be used, but (mis-)using the input field separator characters (space, tab, new-line) is consider at the very least "bad form".
The (mis-)using of characters that are assigned a special purpose in any language, natural or other, in the place of the general purpose characters should only be done when no alternative is available.