FileNameDrop
FileNameDrop["name",n] drops the first n path elements in the file name "name".
FileNameDrop["name",-n] drops the last n path elements in the file name "name".
FileNameDrop["name",{m,n}] drops elements m through n in the file name "name".
FileNameDrop["name"] drops the last path element in the file name "name".
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