Here's my take on that part (no guessing was necessary): sort AAA Delta_SkyMiles Terminal_City_Library Museum_of_Bash_History | uniq -c -d | sort | grep '^

Here's my take on that part (no guessing was necessary): sort AAA Delta_SkyMiles Terminal_City_Library Museum_of_Bash_History | uniq -c -d | sort | grep '^ 4' | cut -d' ' -f8- > ../suspects