AT, Batch & Etc

echo "echo aaa" | at now +1 minutes

echo "xmessage -nearmouse -timeout 20 'asdfasd fdasdf'" | at now +1 minutes

You can also give times like now + count time-units, where the time-units can be minutes, hours, days, or weeks and you can tell at to run the job today by suffixing the time with today and to run the job tomorrow by suffixing the time with tomorrow.