Chain linux commands together

In the Linux shell you can chain a number of command together. You can do a number of command after each other without having to wait for each command to end.

e.g.
touch memtester ; memtester 16M 1 ; rm memtester

The commands is here separated with ; which tells the shell to execute the first command and then it is done it should execute the next command etc.

Another example:
touch memtester && memtester 16M 1 && rm memtester

Here the commands are separated with && which tells the shell to execute the first command and if it completes successfully then execute the next command and etc.