In the previous command Ls/var then in this command LS is the command keyword,/var is the parameter. So how do we do parameter passing when we're making a shell script ourselves?
In bash, the first parameter is automatically placed in $ $, the second parameter is in the $ $, and so on. If the number of arguments is to two digits, then the referenced parameter becomes $ (10) $ (11).
Try it first.
If you want to calculate and value
When programming, it is important to note that the value of the parameter can be used directly, in the calculation and the value of the bracket there should be a space.
Shift
The effect of this command is to invalidate the first parameter, and then go forward one after the other.
I output the same $ $, but the output is not the same
Shift can be followed by the number n, meaning that the previous n parameters are invalidated
N=3 is the first three parameters fail
The value of $ $ has changed when you perform shift 3 o'clock.
To a high-difficulty, calculate the sum of the blank lines of two files
Script passing parameters to the Linux shell script