string realpath ( string $path )
Returns canonicalized absolute pathname
realpath() expands all symbolic links and resolves references to '/./', '/../' and extra '/' characters in the input path and return the canonicalized absolute pathname.
5.3.0 Prior to this release, if only the last path component did not exist, realpath() would not fail on *BSD systems. realpath() now fails in this case. 5.0.0 Prior to this release, a blank or NULL path would cause realpath() to return the directory name of the script.
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