Out of curiousity, are you uncompressing all the files first, then processing them all, then compressing them all, or are you taking each file and uncompressing, processing, and recompressing it before moving on to the next file?

That may or may not make a difference for performance, but it will absolutely make a difference for the disk space used while your script runs.

$;=sub{$/};@;=map{my($a,$b)=($_,$;);$;=sub{$a.$b->()}}
split//,".rekcah lreP rehtona tsuJ";$\=$ ;->();print$/
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