PACK(I)                         12 Dec 75                         PACK(I)

NAME
	pack - compress files

SYNOPSIS
	pack [-] filename ...

DESCRIPTION
	Packs the specified files.  Each input file, f, is replaced by
	a packed file, f.p, with the same mode as that of f.  Packed files
	can be restored to their original form using unpack(I) or pcat(I).

	Pack uses Huffman (minimum redundancy) codes on a byte by byte
	basis.  If the - flag argument is used, the number of times each
	byte is used, its relative frequency, and the code for the byte
	is printed on the standard output.

	The amount of compression obtained depends on the size of the
	input file, and the character distribution.  Since a decoding
	tree forms the first part of the '.p' files, it is not worthwhile
	to pack files smaller than three blocks, unless the character
	distribution is very skewed, such as in printer plots or pictures.
	If no disk blocks are saved by packing, the original file will be
	left unchanged.

	Typically, text files are reduced to 60-75% of their original size;
	Load modules, which use a larger character set and have a more
	uniform distribution of characters, show little compression, the
	packed versions being about 90% of the original size.

RESTRICTIONS
	The last segment of the filename must contain fewer than thirteen
	characters to allow space for the appended '.p' extension.
	Directories cannot (and should not) be compressed.

DIAGNOSTICS
	Several, believed to be self-explanatory.

FILES
	.p files created
	Input files unlinked (unless protected)

SEE ALSO
	unpack(I), pcat(I)

AUTHOR
	Steve Zucker


