[jiyinyiyong]

The philosophy of Unix convinced me at my first glance. But then found there might be some problem in this case.

Just an example. People may say something offer three features, one plus one and plus one, just like Unix does. But if we are going to explain 99, it is faster to say 100 minus 1 rather than 90 plus 9.

`cd $1 && ls` is a larger command. It's also an easier one.