7zip can create gzip compatible archives. Another possibility is Git Extensions (GUI for git), which includes several Unixish command line tools incluging gzip.

Both are open source, so even a code review would be possible.

As for executing, BrowserUk is right - e.g.

my @cmd = (
    'c:\Program Files\7-Zip\7z.exe',
    'a', '-mx9', '-r', 
    'alltexts.zip',
    '*.txt',
    );
system @cmd;
[download]

would work