When you connect via shell/terminal to a server it may not be obvious which type of linux distro it is running. Every distro usually has slightly different ways of doing things, like checking your ipconfig or restarting network adapters. Finding out what version of linux you are working with should be the first step of any sysadmin before running any commands.
#try each one of these commands until one of them works and tells you the OS and version lsb_release -a cat /etc/*release cat /etc/issue* cat /proc/version #the command below works for OpenBSD uname -r