LOL
I have beat you in 1 second......
The * $+ $-1 $+ * or the $+(*,$1-,*) is that it will look for the text in a line.
If you just use $1 , it will do the command only when there is a line which is exactly like $1 (has only $1)
You can also reffer to the line by $readn , This will give you the number of the line.
