There is the undocumented internal function Base.shell_split
that does more-or-less what you want:
julia> Base.shell_split("-f \"C:\\user folder\"")
2-element Vector{String}:
"-f"
"C:\\user folder"
But shelling out sucks because of all the tricksy escaping, and it’s still not clear to me why you want to emulate this behavior in Julia rather than just using Julia as your interface.