gistfile1.rb

#!/usr/bin/ruby

print "Specify dbname: "
dbname = gets.chomp

pids = `psql -U postgres -c "select procpid from pg_stat_activity where datname = '#{dbname}'"`.scan(/^\s+(\d+)$/)
pids.flatten.each do |pid|
  print "Kill #{pid}?[yN] "
  system "sudo kill -9 #{pid}" if gets.chomp.downcase == "y"
end