Am I correct to assume that when `;` joins two commands on a line, Bash always waits until the first command has exited before executing the second command?
And similarly, in a shell script containing two different commands on different lines, Bash always waits until the command on the first line has exited before executing the command on the second line?

If this is the case, is there a way to execute two commands in one line or in a script, so that the second command doesn't wait until the first command has finished?

Also, are different lines in a shell script equivalent to separate lines joined by `;` or `&&`?