Debian – bash: adduser: command not found [Debian Buster]

I have had the same issue with a computer at work. The issue is with the Intel legacy driver and chip sets compatibility with Linux KMS.

According to Intel Support of Chip sets Intel® Atom™ Processor Z500 Series with Intel® Graphics Media Accelerator 500 is no longer supported on Linux. The issue is with KMS (Kernel Mode Setting) is not working with your graphics chip. That is why those higher resolution is no longer available.

Solution sort of :

• Need to edit GRUB2 and Disable KMS on boot up Debian Instructions
• Use XOrg's tool, xrandr (Command line only) or my preferred tool ARandR (Graphical). (Sorry only can post two links so can't add links to the tools)
• See what your highest resolution that is avilable
• Your highest resolution will vary on your non-KMS settings. The best I can do on my work machine is 1280x1028 set with GRUB2.
• Edit GRUB2 to boot to that resolution with disabled KMS.

Things I tried:

1. Extracted the EDID from Windows
2. Created a custom EDID
3. Tried to figure out everything about KMS to see if there was a way to manual make a custom hack to get it to work.

4. Compiling the Intel Legacy Driver

5. Bashing head against a wall

Given the context of wanting to reboot a Linux system, I would take a multi-pronged approach.

First, disable future logins by creating an /etc/nologin file. You could leave it blank or enter informative text in there, such as:

"Logins to this system have been temporarily disabled in preparation for a server reboot, scheduled for (time and date). Please try again after (expected end time)."

Don't forget to remove /etc/nologin when you're done!

Additionally, since a reboot will clear all processes, whether they're interactive or not, I would use ps to look for processes owned by users. This will take some manual investigation to determine whether the processes are worth keeping or not, but should narrow the field some. I've hard-coded 1000 here as the value of UID_MIN from /etc/login.defs as the cutoff for "system" vs "user" UIDs. If any of your users have UIDs below 1000, you'll need to adjust that number.

ps -eo pid,uid,args | awk '$2 >= 1000'

Of course, you could adjust the ps columns to taste, perhaps to add the translated username and process start time (ps -eo pid,uid,user,start,args) or others -- just be careful to keep the ps UID and awk field in sync with each other.

To get the list of unique user names, use:

ps -eo user,uid | awk 'NR>1 && $2 >= 1000 && ++seen[$2]==1{print $1}'