check computers connected to network ubuntu
I always use nmap. To scan for all devices in your network, use:
nmap -sP 192.168.0.1/24
More here: https://www.cyberciti.biz/networking/nmap-command-examples-tutorials/
It is a great tool to know about. You may want to install nmap using:
sudo apt-get install nmap if you are using Debian or
sudo pacman -S nmap if you are using Arch.