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A general description is here.
sprintf() now supports '%o' for octal conversions.
New function Sys.readlink() for information about symbolic links.
In registering an S3 class by a call to setOldClass(), the data part (e.g., the object type) required for the class can be included as one of the superclasses in the Classes argument.
The argument f= to showMethods() can be an expression evaluating to a generic function, allowing methods to be shown for non-exported generics and other nonstandard cases.
New function tar() to create (possibly compressed) tar archives.