If you’d like to run multiple commands in shell which is executed one by one, you can simply type:
command1; command2; command3.... commandn
What if you need to run all these jobs in parallel. When you have just single command you can add & and the command will be executed in the background. So the temptation for a solution might be:
command1 &; command2 &;... commandn &
Well, it does not work. The correct solution for oneliners is simple. Just replace ; by &
command1 & command2 & command3 & ... commandn
The same solutions works also for other shells like zsh.