[0m


PACK(1V)	    UNIX Programmer's Manual		 PACK(1V)



[1mNAME
     [0mpack, unpack, pcat - compress and uncompress files

[1mSYNOPSIS
     /usr/5bin/pack [0m[ [1m- [0m] [ [1m-f [0m] _f_i_l_e...
     [1m/usr/5bin/unpack [0m_f_i_l_e...
     [1m/usr/5bin/pcat [0m_f_i_l_e...

[1mDESCRIPTION
     [0m_P_a_c_k is a utility for compressing files.  When it is possi-
     ble to effect a space saving, each _f_i_l_e is replaced by a
     packed file called _f_i_l_e._z with identical access permissions,
     last-access and modified times as _f_i_l_e.

     A file will not be packed if: it is already packed; it has
     hard links; it is a directory; it cannot be opened; it is
     empty; no disk saving will result; a file called _n_a_m_e._z can-
     not be opened (or already exists) or an I/O error occurs
     during packing.

     The exit status of _p_a_c_k is the number of files that were not
     packed.

     _U_n_p_a_c_k uncompresses files created with _p_a_c_k.  Each _f_i_l_e is
     sought, with `.z' appended to its name if necessary, is
     unpacked and replaced with the expanded version.  The new
     file has the `.z' suffix removed, and has the same access
     permissions and last-access and modification dates as the
     packed file.

     _U_n_p_a_c_k will fail to expand a file if: the packed file cannot
     be opened; the file does not appear to be packed; the output
     file cannot be created or already exists.

     The exit status of _u_n_p_a_c_k is the number of files it failed
     to unpack.

     _P_c_a_t unpacks one or more files, concatenates the result, and
     writes it to standard output.  The packed files are not
     deleted or replaced.  As with _u_n_p_a_c_k, a `.z' suffix is
     appended to the filenames if not already present.

     _P_c_a_t may fail to unpack a file if it cannot be opened or its
     contents do not appear to be packed.  Its exit status is the
     number of files it failed to expand.

[1mOPTIONS
     [0m_P_a_c_k accepts two options:

     [1m-	     [0mDisplay compression statistics for the names follow-
	     ing.  Subsequent occurences between filenames tog-
	     gles statistics on and off.



Printed 1/11/93     Revision 1.1 of 10/10/90			1






PACK(1V)	    UNIX Programmer's Manual		 PACK(1V)



     [1m-f      [0mForce packing even if no space saving will result.

[1mPACKING METHOD
     [0mThe packing algorithm used is Huffman encoding.  The space
     saving obtained depends very heavily on the nature of the
     original data: English text is typically compressed by 25 to
     40 percent, while object code files may show as little as a
     10 percent reduction.

[1mSEE ALSO
     [0mcompress(1), uncompress(1), zcat(1)

[1mBUGS
     [0mPacked files may not unpack correctly on other systems.









































Printed 1/11/93     Revision 1.1 of 10/10/90			2



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