in the instance of a file compressed with compress to a .Z extension...

how would I, in the Bourne Shell, capture its compression ratio? Gunzip returns -1 and I'd then gone down the track of roughly calculating the ratio (not including time) manually.

Until I found out the Bourne Shell doesn't do calculations!

So I am perplexed. I am stuck in the Bourne Shell, I'm not permitted to use anything else - what function returns the compression ratio in a manner I can capture.

There was one process with a -v verbose option but it would not pipe to echo or > to a file from memory.

Strategically stuck is the phrase.