Block (from Samuel Mullen on Legacy Rocks slack)

productivity.sh

# List the domains you want to block, one per line, in your ~/.blocked_sites file,
# then ensure this script is included or sourced in your terminal configuration.

function worktime {
  while read -r line; do
    echo "127.0.0.1 ${line} # WORKTIME"
    echo "fe80::1%lo0 ${line} # WORKTIME"
    echo "127.0.0.1 www.${line} # WORKTIME"
    echo "fe80::1%lo0 www.${line} # WORKTIME"
  done < $HOME/.blocked_sites | sudo tee -a /etc/hosts > /dev/null
}

function slacktime {
  while read -r line; do
    [[ $line =~ "# WORKTIME" ]] && continue
    echo $line
  done < /etc/hosts > /tmp/hosts

  sudo cp /tmp/hosts /etc/hosts
}