You may wonder how you knowing the hostname or machine type you are log in. Actually we have a lot way to do so, one of them is print out the environment variable set. How we can set this variable? export is the command used in bash shell, example:
export VARIABLE_NAME="any data you want to put in"
to display the variable set, echo can be use to display it:
To print out environment variable using ‘echo’, ‘$’ (dollar sign) must put in front of the variable name.