Advanced Bash−Scripting Guide

Advanced Bash−Scripting Guide
• newstring=`capitalize_ichar "each sentence should start with a capital letter."`
echo "$newstring"
# Each sentence should start with a capital letter.
It is even possible for a function to "return" multiple values with this method.
Example 34−11. Even more return value trickery
#!/bin/bash
# sum−product.sh
# A function may "return" more than one value.
sum_and_product () # Calculates both sum and product of passed args.
{
echo $(( $1 + $2 )) $(( $1 * $2 ))
# Echoes to stdout each calculated value, separated by space.
}
echo
echo "Enter first number "
read first
echo
echo "Enter second number "
read second
echo
retval=`sum_and_product $first $second` # Assigns output of function.
sum=`echo "$retval" | awk '{print $1}'` # Assigns first field.
product=`echo "$retval" | awk '{print $2}'` # Assigns second field.
echo "$first + $second = $sum"
echo "$first * $second = $product"
echo
exit 0
• Next in our bag of trick are techniques for passing an array to a function, then "returning" an array
back to the main body of the script.
Passing an array involves loading the space−separated elements of the array into a variable with
command substitution. Getting an array back as the "return value" from a function uses the previously
mentioned strategem of echoing the array in the function, then invoking command substitution and
the ( ... ) operator to assign it to an array.
Example 34−12. Passing and returning arrays
#!/bin/bash
# array−function.sh: Passing an array to a function and...
# "returning" an array from a function
Pass_Array ()
{
local passed_array # Local variable.
passed_array=( `echo "$1"` )
echo "${passed_array[@]}"
# List all the elements of the new array
Chapter 34. Miscellany 351