The following lines were added (+) and removed (-):
(A) run several commands using the control operator ";" (semicolon) which will execute them sequentially. The shell will wait for each command to terminate in turn. The return status is the exit status of the last command executed.(B) run several commands using the control operator "&" (ampersand) echo 1 & sleep 5s & echo 2(C) run several commands using double ampersands