freebsd man page for sq

SQ(1)							      General Commands Manual							     SQ(1)

NAME
       sq, unsq - squeeze or unsqueeze a sorted word list

SYNOPSIS
       sq < infile > outfile

       unsq < infile > outfile

DESCRIPTION
       sq compresses a sorted list of words (a dictionary).  For example:
	      sort -u /usr/share/dict/words | sq | gzip -9 > words.sq.gz
       will compress dict by about a factor of 5.

       unsq uncompress the output of sq.  For example:
	      gunzip < words.sq.gz | unsq | sort -f -o words
       will uncompress a dictionary compressed with sq.

       The squeezing is achieved by eliminating common prefixes, and replacing them with a single character which encodes the number of characters
       shared with the preceding word.	The prefix size is encoded as a single printable character: 0-9 represent 0-9, A-Z represent 10-35, and a-
       z represent 36-61.

BUGS
       sq and unsq can only handle words of up to 256 characters.  The input must be sorted, and duplicates must be suppressed.

AUTHOR
       Mike Wexler

SEE ALSO
       compress(1), sort(1).

								       LOCAL								     SQ(1)