EOF is short for end-of-file mark, a special character or sequence of characters that marks the end of a file.
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Operating systems need to keep track of where every file ends. There are two techniques for doing this: One is to put a special end-of-file mark at the end of each file. The other is to keep track of how many characters are in the file.
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In many operating systems, including DOS and OS/2, the end-of-file mark is CTRL -Z.
