man sq (Commandes) - squeeze a sorted word list unsq - unsqueeze a sorted word list
NAME
sq - squeeze a sorted word list unsq - 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 /usr/share/dict/words | sq | compress > words.sq.Z will compress dict by about a factor of 4.
unsq uncompress the output of sq. For example: compress -d < words.sq.Z | 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.
AUTHOR
Mike Wexler