Creating a Temporary Cron Job From the Terminal

Question

Is there a way to create a temporary one-time only cron job from the command line? I'd like to have an egg-timer like function to open a terminal and do:

notify "time is up" 30

which would simply run this after 30 minutes:

zenity --info --text="time is up"

It seems easy enough for me to create, but I'm having a hard time believing no one has created something similar. Searching Ubuntu's repository for timing packages doesn't show anything. Has this been done before?

Answer 1

Use the at command.

$ at now + 30 minutes
at> zenity --info --text="time is up"
at> ^D     (press CTRL-D)

The time format is pretty flexible. Here are a bunch of examples.

$ at 11:45

$ at 0800 Friday

$ at 4pm + 3 days

$ at 9am tomorrow