Shell Programming and Scripting

#/bin/bash
for f in {1..13}
do
     c=$((RANDOM%8+2))
     echo chr$f - $c records
     for((l=0;l<c;l++))
     do
         echo $((RANDOM%10)) >> index/chr$f
     done
     for s in {1..83}
     do
         [ $f -eq 1 ] && mkdir data/Subfolder$s
         for((l=0;l<c;l++))
         do
             echo $((RANDOM%10)) >> data/Subfolder$s/chr$f
         done
     done
done