Shell Programming and Scripting

x=(a b c)
y=(d e)
times=$((${#x[*]} * ${#y[*]}))
((xi=yi=0))
for((i=1;i<=times;i++,xi++,yi++))
do
 if((xi>${#x[*]}-1));then xi=0;fi
 if((yi>${#y[*]}-1));then yi=0;fi
 print ${x[$xi]},${y[$yi]}
done

a,d
b,e
c,d
a,e
b,d
c,e

x=(a b c)
y=(d e)
times=$((${#x[*]} * ${#y[*]}))    ### times = (length of array x)*(length of array y)=3*2=6
((xi=yi=0))                       ### xi - index for accessing elements of array x (in the loop)
                                  ### yi - index for accessing elements of array y (in the loop)
for((i=1;i<=times;i++,xi++,yi++)) ### loop "times" (6) times
do                                ### Remember, for indexed arrays, indexing starts at 0.
 if((xi>${#x[*]}-1));then xi=0;fi ### reset xi if it goes over the value of (length of array x - 1)
 if((yi>${#y[*]}-1));then yi=0;fi ### reset yi if it goes over the value of (length of array y - 1)
 print ${x[$xi]},${y[$yi]}        ### print elements from x and y indexed by xi and yi, respectively
done