If you have a server at home and you want it to be on only during specific times and not 24⁄7, this script is for you.
Cron not only is the best tool for this, it also handles scheduled tasks.
Cron is a system daemon used to execute desired tasks (in the background) at designated times.
Install Cron on Ubuntu if it is not already installed.
Create a new file, suspend_until, in your ~/Documents/ and place the following contents in it. This script is written by Romke van der Meulen.
#!/bin/bash # Auto suspend and wake-up script # # Puts the computer on standby and automatically wakes it up at specified time # # Written by Romke van der Meulen <firstname.lastname@example.org> # Minor mods fossfreedom for AskUbuntu # # Takes a 24hour time HH:MM as its argument # Example: # suspend_until 9:30 # suspend_until 18:45 # ------------------------------------------------------ # Argument check if [ $# -lt 1 ]; then echo "Usage: suspend_until HH:MM" exit fi # Check whether specified time today or tomorrow DESIRED=$((`date +%s -d "$1"`)) NOW=$((`date +%s`)) if [ $DESIRED -lt $NOW ]; then DESIRED=$((`date +%s -d "$1"` + 24*60*60)) fi # Kill rtcwake if already running sudo killall rtcwake # Set RTC wakeup time # N.B. change "mem" for the suspend option # find this by "man rtcwake" sudo rtcwake -a -m disk -t $DESIRED & # feedback echo "Suspending..." # give rtcwake some time to make its stuff sleep 2 # then suspend # N.B. dont usually require this bit #sudo pm-suspend # Any commands you want to launch after wakeup can be placed here # Remember: sudo may have expired by now # Wake up with monitor enabled N.B. change "on" for "off" if # you want the monitor to be disabled on wake xset dpms force on # and a fresh console clear echo "Good morning!"
Change the permission of the file so that it is executable.
$ sudo chmod +x ~/Documents/suspend_until
- Run crontab.
$ sudo crontab -e
Place the following line at the end of the file.
00 02 * * * /home/user/Documents/suspend_until 09:00
This basically tells the server to execute the suspend_until script at 2:00 AM. The 09:00 appended at the end of the line tells the server to wake up at 9:00 AM. The details are all explained in the script.
- Save the crontab file and reboot.