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Annotation of 43BSDTahoe/old/man/compact.0, revision 1.1

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        !             4: COMPACT(1)         UNIX Programmer's Manual           COMPACT(1)
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        !             8: NAME
        !             9:      compact, uncompact, ccat - compress and uncompress files,
        !            10:      and cat them
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        !            12: SYNOPSIS
        !            13:      compact [ -v ] [ name ... ]
        !            14:      uncompact [ -v ] [ name ...  ]
        !            15:      ccat [ -v ] [ file ... ]
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        !            17: DESCRIPTION
        !            18:      _C_o_m_p_a_c_t compresses the named files using an adaptive Huffman
        !            19:      code.  If no file names are given, the standard input is
        !            20:      compacted to the standard output. _C_o_m_p_a_c_t operates as an
        !            21:      on-line algorithm.  Each time a byte is read, it is encoded
        !            22:      immediately according to the current prefix code. This code
        !            23:      is an optimal Huffman code for the set of frequencies seen
        !            24:      so far.  It is unnecessary to prepend a decoding tree to the
        !            25:      compressed file since the encoder and the decoder start in
        !            26:      the same state and stay synchronized.  Furthermore, _c_o_m_p_a_c_t
        !            27:      and _u_n_c_o_m_p_a_c_t can operate as filters.  In particular,
        !            28: 
        !            29:          ... | compact | uncompact | ...
        !            30: 
        !            31:      operates as a (very slow) no-op.
        !            32: 
        !            33:      When an argument _f_i_l_e is given, it is compacted and the
        !            34:      resulting file is placed in _f_i_l_e._C; _f_i_l_e is unlinked.  The
        !            35:      first two bytes of the compacted file code the fact that the
        !            36:      file is compacted.  This code is used to prohibit recompac-
        !            37:      tion.
        !            38: 
        !            39:      The amount of compression to be expected depends on the type
        !            40:      of file being compressed. Typical values of compression
        !            41:      are: Text (38%), Pascal Source (43%), C Source (36%) and
        !            42:      Binary (19%).  These values are the percentages of file
        !            43:      bytes reduced.
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        !            45:      _U_n_c_o_m_p_a_c_t restores the original file from a file compressed
        !            46:      by _c_o_m_p_a_c_t. If no file names are given, the standard input
        !            47:      is uncompacted to the standard output.
        !            48: 
        !            49:      _C_c_a_t cats the original file from a file compressed by _c_o_m_-
        !            50:      _p_a_c_t, without uncompressing the file (it is just a shell
        !            51:      script which directs the uncompacted output to the standard
        !            52:      output).
        !            53: 
        !            54:      _C_o_m_p_a_c_t, _u_n_c_o_m_p_a_c_t, and _c_c_a_t normally do their work
        !            55:      silently. If a -v flag is supplied, _c_o_m_p_a_c_t will report the
        !            56:      compression percentage for each compacted file while _u_n_c_o_m_-
        !            57:      _p_a_c_t and _c_c_a_t will print out the name of each file as
        !            58:      they're uncompacted.
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        !            63: Printed 7/26/87          April 29, 1985                         1
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        !            69: 
        !            70: COMPACT(1)         UNIX Programmer's Manual           COMPACT(1)
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        !            74: RESTRICTION
        !            75:      The last segment of the filename must be short enough to
        !            76:      allow space for the appended '.C'.
        !            77: 
        !            78: FILES
        !            79:      *.C       compacted file created by compact, removed by
        !            80:      uncompact
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        !            82: SEE ALSO
        !            83:      Gallager, Robert G., `Variations on a Theme of Huffman',
        !            84:      _I._E._E._E.  _T_r_a_n_s_a_c_t_i_o_n_s _o_n _I_n_f_o_r_m_a_t_i_o_n _T_h_e_o_r_y, vol. IT-24,
        !            85:      no. 6, November 1978, pp. 668 - 674.
        !            86: 
        !            87: AUTHOR
        !            88:      Colin L. Mc Master
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        !           129: Printed 7/26/87          April 29, 1985                         2
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