Sudo ip addr add dev eth0

sudo ip addr add dev eth0 what does dev mean ?

@ajey, that means that you are setting the ipaddress for the system. Usually eth0 is the primary interface for Linux based systems.
And since you are using sudo, it probably means that you are not a root user. So, any user with sudo permissions to execute the above command( need to be set in sudoers file), can execute the above command and set the IP.

@ajey dev refers to “device”.