typeset - arrays

gistfile1.txt

#!/bin/bash                                                                                                                                                                                                                                                               
                                                                                                                                                                                                                                                                          
# Sum a set of arrays and assign the result indirectly, also printing each intermediary result (without portability workarounds)                                                                                                                                          
# sum name arrname [ arrname ... ]                                                                                                                                                                                                                                        
function sum {                                                                                                                                                                                                                                                            
    typeset -n _result=$1 _arr                                                                                                                                                                                                                                            
    typeset IFS=+                                                                                                                                                                                                                                                         
    _result=0                                                                                                                                                                                                                                                             
    for _arr in "${@:2}"; do                        # Demonstrate the special property of "for" on a nameref.                                                                                                                                                             
        (( _result += ${_arr[*]} ))                                                                                                                                                                                                                                       
        printf '%s = %d\n' "${!_result}" "$_result" # Demonstrate the special property of ${!ref} on a nameref.                                                                                                                                                           
    done                                                                                                                                                                                                                                                                  
}                                                                                                                                                                                                                                                                         
                                                                                                                                                                                                                                                                          
a=(1 2 3) b=(6 5 4) c=(2 4 6)                                                                                                                                                                                                                                             
sum total a b c                                                                                                                                                                                                                                                           
printf 'Final value of "total" is: %d\n' "$total"