> you could consider rubyzip:
>
> =A0 require 'zip/zipfilesystem'
> =A0 Zip::ZipFile.open("foo.zip") { |zfs|
> =A0 =A0 zfs.file.open("member.txt") { |f| f << data }
> =A0 =A0 zfs.commit
> =A0 }

This is *exactly* what I need to be able to do, except with .tar.gz
files.  I will use this solution for now, even while still searching
for (or maybe writing) the .tar.gz equivalent.  Short term, this will
get me by...  [even though a .tar.gz equivalent would be really nice].

Thanks!!