Checks path is valid

Not meant to be called directly

.check_valid_command_path(path)

Arguments

path	path to file or directory

Value

expanded system path

Examples

if (.Platform$OS.type == "unix" & file.exists("~/bin")) {
# will return /full/path/to/home/bin, or error if path doesn't exist
.check_valid_command_path("~/bin")
}