http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap03.html#…
http://www.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap04.html#…
POSIX.2, in its description of 'cd', says that three or more leading slashes may be replaced with a single slash when canonicalizing the current working directory.
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trey @ gépház