$2\mathrm{.}1$ Task $1$: Manipulating Environment Variables

In this task, we study the commands that can be used to set and unset environment variables. We are using

Bash in the seed account. The default shell that a user uses is set in the $/$etc$/$passwd file $($the last field

of each entry$).$ You can change this to another shell program using the command chsh $($please do not do it

for this lab$).$ Please do the following tasks:

$$ Use printenv or env command to print out the environment variables. If you are interested in

some particular environment variables, such as PWD$,$ you can use "printenv PWD$"$ or "env $|$

grep PWD$".$

$$ Use export and unset to set or unset environment variables. It should be noted that these two

commands are not separate programs; they are two of the Bash$$s internal commands $($you will not be

able to find them outside of Bash$).$