Note how we ran four processes at the same time, by using the & symbol. Doing so runs a
job in the background in the zsh shell, which means that the user is able to immediately issue
their next command, which in this case is another program to run. If you’re using a different
shell (e.g., tcsh), it works slightly differently; read documentation online for details.
Ctrl+C seems to halt the execution of jobs running in the foreground