Find a public Google group for a particular host. Some of these groups contain sensitive information. The tool runs against a list of hosts and returns all public groups.

googlegroups.sh

#!/bin/bash

# Find a public Google group for a particular host. 
# Some of these groups contain sensitive information. 
# The tool runs against a list of hosts and returns all public groups.

while read domain; do
    if curl -LIs "https://groups.google.com/a/$domain" | grep "overview" > /dev/null; then
        echo "[+] https://groups.google.com/a/$domain/forum/#!overview"
    fi
done < $1

The results above are with 100 domains that are either private or 404. For those curl makes 2 request (1 redirect), not 3.
If you take 100 public domains, then the difference in run time is higher (3 requests / domain vs. 1 request).

Before:
./googlegroups_old.sh 100public 6,29s user 1,50s system 3% cpu 3:48,46 total

After:
./googlegroups.sh 100public 6,20s user 1,56s system 7% cpu 1:38,67 total

3:48 > 1:38
200 requests and more than 2 minutes saved, only on 100 domains.

Nice work, @milangfx! I wrote this merely as a proof of concept — not focusing on performance. If you really want performance, don't write a while loop in the script itself. Just have the script issue the requests and then run it using GNU parallel.

Thanks for the feedback. I was focusing on efficiency in a single threaded case. Making the same request run in parallel would be faster, but still inefficient.