This method has gained influence within North America, as most common computer filesystems make the use of slashes difficult or impossible. DOS, OS/2 and Windows simultaneously support both \ and / as directory separators, but / is also used to introduce and separate switches to shell commands (unless reconfigured to use the hyphen-minus in DOS). Unix-like systems use / as a directory separator and, while \ is legal in filenames, it is awkward to use as the shell uses it as an escape character. Unix also uses a space followed by a hyphen to introduce switches. Apart from the separator used the non-year form of the date format is also identical to the standard American representation.