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Annotation of cci/usr/src/man/man1/compact.1, revision 1.1

1.1     ! root        1: .TH COMPACT 1 "18 January 1983"
        !             2: .UC 4
        !             3: .SH NAME
        !             4: compact, uncompact, ccat \- compress and uncompress files, and cat them
        !             5: .SH SYNOPSIS
        !             6: .B compact
        !             7: [ name ... ]
        !             8: .br
        !             9: .B uncompact
        !            10: [
        !            11: name ...
        !            12: ]
        !            13: .br
        !            14: .B ccat
        !            15: [ file ... ]
        !            16: .SH DESCRIPTION
        !            17: .I Compact
        !            18: compresses the named files using an adaptive Huffman code.  If no file
        !            19: names are given, the standard input is compacted to the standard output.
        !            20: .I Compact
        !            21: operates as an on-line algorithm.  Each time a byte is read,
        !            22: it is encoded immediately according to the current prefix code.
        !            23: This code is an optimal Huffman code for the set of frequencies seen so far.
        !            24: It is unnecessary to prepend a decoding tree to the compressed file
        !            25: since the encoder and the decoder start in the same state and stay
        !            26: synchronized.  Furthermore,
        !            27: .I compact
        !            28: and
        !            29: .I uncompact
        !            30: can operate as filters.  In particular,
        !            31: .sp
        !            32:        ... | compact | uncompact | ...
        !            33: .br
        !            34: .sp
        !            35: operates as a (very slow) no-op.
        !            36: .PP
        !            37: When an argument
        !            38: .I file
        !            39: is given, it is compacted and the resulting file is placed in
        !            40: .I file.C;
        !            41: .I file
        !            42: is unlinked.  The first two bytes of the compacted file code the
        !            43: fact that the file is compacted.  This code is used to prohibit recompaction.
        !            44: .PP
        !            45: The amount of compression to be expected depends on the type of file being
        !            46: compressed.  Typical values of compression are:
        !            47: Text (38%), Pascal Source (43%), C Source (36%) and Binary (19%).
        !            48: These values are the percentages of file bytes reduced.
        !            49: .PP
        !            50: .I Uncompact
        !            51: restores the original file from a file compressed by
        !            52: .I compact.
        !            53: If no file names are given, the standard input is uncompacted to
        !            54: the standard output.
        !            55: .PP
        !            56: .I Ccat
        !            57: cats the original file from a file compressed by
        !            58: .I compact,
        !            59: without uncompressing the file.
        !            60: .SH RESTRICTION
        !            61: The last segment of the filename must contain fewer than thirteen characters
        !            62: to allow space for the appended '.C'.
        !            63: .SH FILES
        !            64: .ta 1i
        !            65: *.C    compacted file created by compact, removed by uncompact
        !            66: .SH "SEE ALSO"
        !            67: Gallager, Robert G., `Variations on a Theme of Huffman',
        !            68: .I "I.E.E.E.  Transactions on Information Theory,"
        !            69: vol. IT-24, no. 6, November 1978, pp. 668 - 674.
        !            70: .SH AUTHOR
        !            71: Colin L. Mc Master

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