Some Examples
a | b | c
- connects standard output of one program to standard input of another
- shell runs the entire set of processes in the foreground
- prompt appears after c completes
a & b & c
- executes a and b in the background and c in the foreground
- prompt appears after c completes
a & b & c &
- executes all three in the background
- prompt appears immediately
a | b | c &
- same as first example, except it runs in the background and prompt appears immediately