I want to know if there is any way we can make either Windows or Linux machine shut down for let's say "N" minutes. and then it powers up automatically at the end of "N" minutes.
I know we can switch between OS using Grub from Linux and using third party software on Windows but never heard of such software or command to make it shut-down for certain time.
Check your BIOS, sometimes motherboards have a "boot at specific time" option in there if it's a regular thing
If you machine doesn't need to be fully off, then you could also hibernate. rtcwake is popular, allows disk-written low power hibernation and can be set to come back up automatically
Lastly if you need (or want, for energy reasons) it to be for reals off, and you don't have a timer boot option, most motherboards allow "Wake on LAN" or "Power by Eth" or something along those lines. Keeps enough power going to the network card to detect a broadcast packet with a wakeup signal matching your machine's NIC's MAC address from the network, even when the computer has properly shutdown. This is my favourite method because it's true remote boot, but it means you need to have another device on the network.
There are readily available phone apps which can send a wake signal, I've only ever used manual ones but there's bound to be one on a timer. For linux I know there's ethtool and wakeonlan available, (haven't used either personally though.) Worst case scenario, there are several tutorials for baking your own, and the protocol isn't complex.
For Windows:
To my understanding you need to create a new task on the Windows Task Scheduler and let that task run after N minutes. The scheduler will program the BIOS' "power up on time" feature to the specified time. If the machine is powered (plugged in to wallsocket) and Windows is only in standby or hibernate mode (that is, not shut down), it should power up on the given time. You might want to set the waking time about a minute early or so, since booting takes time as well. Also make sure energy saving options are not set too strict like "go to standby after X minuted of idle time" and this is in the middle of the unattended task execution ;) I used this a lot when programming my PC to record from my TV card on a specific date and time and it worked well. DVBViewer handled all of the task creating stuff. I never set them up manually. There surely are other tools to automate the task creation if needed.
The manual way is something like this: Right click on the Windows Start Button, select "Computer Administration Console" (or similar, I don't know the correct english naming), then a window pops up where you can right click in the tree view on the left handside on the item "Task Scheduler" (again, naming may differ) and select "Create simple Task" or "New Task..." (more advanced options). Hope you can manage from there. Should work on Windows 7 to 10. Maybe earlier versions as well, but you need to figure out how to get to the task creation wizard.
Hope this helps, good luck :)
