Show running processes without the system processes

Processes can easily be filtered by user. In htop, press u and select a user name, or run htop -u $(id -un). You can also make other users' processes visible but grayed out by ticking “Setup → Display options → Shadow other users' processes”.

The “desktop stuff” are processes running under your user. There's no concept of “process that's part of the desktop stuff” vs “process that's an independent application”. As far as the operating system is concerned, the parts that make up the “desktop stuff” are applications like any other. The definition of “desktop stuff” vs “other stuff” is purely arbitrary. A program launched manually by clicking on an icon is indistinguishable from a widget that was started automatically at the start of the session.

If you run programs from a terminal, you can run the ps command in a terminal. By default, it lists only programs started from that terminal.

While you could list all the programs started from any terminal, that wouldn't be meaningful, since it wouldn't include programs started from a desktop menu or icon.

If you're only interested in GUI programs that aren't part of the desktop, listing windows would be more meaningful. Try wmctrl -lp.

If you want to see all processes belonging to user $USER in top, either press u and enter the username, or start top with

$ top -U $USER 

To get a simple list of processes on the command line:

$ pgrep -l -U $USER 

A similar list with ps:

$ ps -U $USER 

According to the htop manual, this would start htop showing only the processes belonging to user $USER:

$ htop -u $USER 

Note that the variable USER usually contains your own username. I'm using it here as an example.

Try using

ps aux | grep ubuntu 

Replace ubuntu with your desktop username. Your system users may be root, syslog, etc

If you're not sure of your username, on the terminal issue :~$ whoami

You should see something like

ubuntu@ip-172-31-46-27:~$ whoami ubuntu