Shell script - positional parameters (command line parameters)

function Shell We can pass some parameters to the script file , These parameters can be used inside the script file $n To receive , for example ,$1 Represents the first parameter ,$2 Represents the second parameter , By analogy .

Pass location parameters to the script file

The script is as follows ：

#!/bin/bash

echo "name: $1"
echo "age: $2"

Carry out orders ：sh test.sh jack 18, among jack Is the first positional parameter ,18 Is the second position parameter , The two are separated by spaces . Output is as follows ：

name: jack
age: 18

Passing positional parameters to a function

The script is as follows ：

#!/bin/bash

# Defined function 
function func(){
        echo "name: $1"
        echo "age: $2"
}

# Call function 
func jack 20

Output ：

name: jack
age: 20

matters needing attention

If there are too many parameters , Reach or exceed 10 individual , Then we have to use ${n} To receive , for example ${10}、${23}.{ } The function of is to help the interpreter identify the boundary of parameters , This is the same as adding... When using variables { } It's the same effect .