for TERMINAL in $(./terminals --online); do
  echo "${TERMINAL}t"
  termssh ${TERMINAL}.mydomain.com sudo usermod -aG systemd-journal myuser &&
    echo ok ||
    echo ERROR
done

alias termssh='/usr/bin/ssh -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no -o ConnectTimeout=5'

while read TERMINAL; do
  echo "${TERMINAL}t"
  termssh ${TERMINAL}.mydomain.com sudo usermod -aG systemd-journal myuser &&
    echo ok ||
    echo ERROR
done < <(./terminals --online)