如果我已登錄，如何在預定的時間啟動程序？

Look at this command called at http://manpages.ubuntu.com/manpages/gutsy/man1/at.1posix.html you can execute commands at a specific time Use this to launch your application at a specific time

Assuming this application is a graphical application that requires an X display to connect to, I'd write a script that sleeps for X seconds then runs the application, where X is the number of seconds until the desired time. Then run this via Startup Applications.

Something like this:

#!/usr/bin/env bash

# run at 16:30
h=16 m=30

while true; do 
    # grab current hour and minute
    read now_h now_m < <(date "+%H %M")

    # calculate approximate number of seconds until 16:30 using modular 
    # arithmetics
    (( s = (1440 + (10#$h*60 + 10#$m) - (10#$now_h*60 + 10#$now_m)) % 1440 * 60 ))

    printf "Sleeping %d seconds\n" "$s"
    sleep "$s" && theapp
done

That should run the app somewhere between 16:30 and 16:31 each day while you're logged in.

I would write a script to be run by CRON.

To check if a user is logged in:

who -a | grep fred

Where fred is the user name you want to check for.

ps -ef | grep appname

Will return something if it finds appname running so you can check for that.

Make sure that you run the script with the appropriate user credentials (root?)

So, for example here is a bash script snippet that shows testing for the output from the cmd | grep ....:

#!/bin/bash

if who -a | grep fred > /dev/null; then
   echo "Fred is logged in"
   if ps -ef | grep appname > /dev/null; then
      echo "User is logged in and app is running"
   else
      echo "User is logged in BUT appname is not running"
      # ---- Do stuff here ----
   fi
else
   echo "Fred is NOT logged in"
fi

One thing to note is that the way I've coded grep means that it does a wild-card search by default so grep jul would find julian and july, etc.

Another option is to use Scheduled tasks with it can you can specify a lot of things https://apps.ubuntu.com/cat/applications/gnome-schedule/ download it at apt://gnome-schedule