Well they could use an ordinary pipe, but they would have to group the later expression in parantheses. In bash the | creates a fork, so if you try: echo "sdfs

Well they could use an ordinary pipe, but they would have to group the later expression in parantheses. In bash the | creates a fork, so if you try: echo "sdfsdf" | read sid && echo $sid you get a blank line, but if you try: echo "sdfsdf" | (read sid && echo $sid) you get "sdfsdf" |& is an abbreviation for >2&1 | . In zsh the grouping isn't needed, the expression works out of the box. For more information on the subject: http://stackoverflow.com/questions/13763942/bash-why-piping-input-to-read-only-works-when-fed-into-while-read-const http://stackoverflow.com/questions/13763942/bash-why-piping-...