Shell splits strings into Arrays

#! /Bin/bash
A = "one, two, three, four"
# To split $ A, you can:
Old_ifs = "$ ifs"
Ifs = ","
Arr = ($)
Ifs = "$ old_ifs"
For s in $ {arr [@]}
Do
Echo "$ S"
Done
The above code will output
One
Two
Three
Four

Arr = ($ A) is used to split string $ A into arrays $ arr $ {arr [0] }$ {arr [1]}... respectively store the split array 1st 2... item, $ {arr [@]} stores the entire array. The variable $ ifs stores the delimiter. Here we set it to comma
"," Old_ifs is used as the default backup separator to restore the default backup after use

The command used to execute integer arithmetic operations in Bash is let;
The syntax format is: let arg ....

For example, let
J = I * 6 + 2 is equivalent to (j = I * 6 + 2 ))