Q: Data transfer seems to continue forever and the output shows that well over 100% of the data has been transported. Is this normal?
A: This is not normal. This kind of error has occurred several times, but so far we don't know what is causing this Please kill your data transfer process (Ctrl-c) and try running the same command again.
Q: How I can download the data with a-get without having to download each individual object using a separate a-get command?
A: I am afraid that you have to run a-get commands one by one.
What you can do is first create a list of objects to be downloaded:
a-list your-bucket | grep "some-regexp" > object_list
And then use the list in a for loop
for ob in $(cat object_list)
do
a-get $ob
done