What command lists all of your environment variables? a. printeny b. show env c. show alleny Please G d. printenv QUESTION 7 When you want to reference an environment variable you use what character in front of the variable name? a. & b.@ c. $ d. 96 QUESTION 8 1 points What does the pipe (1) command do? a. None of the above. b. A mechanism by which the input of one program can be sent as the output to another program, C. A mechanism by which the output of one program can be sent as the input to another program. d. A mechanism by which the output and input to one program