Shell custom function

1 grammar

#  Definition of function 
[ function ] funname ()
{
    
     command 
    [return  Return value ]

}

#  Call function 
funname  Pass parameters 1  Pass parameters 2 ...

2 demo

 #!/bin/bash
fun1()
{
     
  echo " Call parameterless function "
}

fun2()
{
    

 echo " Find the sum of two numbers ..." 
 read -p " Enter the first number : " n1
 read -p " Enter the second number : " n2
 return $(($n1+$n2))
}

fun3()
{
    
  echo " The first parameter is zero :${1}" 
  echo " The second parameter is :${2}"

  return $(($1+$2))
}


# Call parameterless function 
fun1
# Call return function 
fun2
rs=`echo $?`
echo " The sum of two numbers is : ${rs}"
# Call the third function 
fun3 2 2
rs=`echo $?`
echo "fun3  The return result is : ${rs}"