Bash wordlist/dictionary generator for brute-forcing

This example code will generate passwords of 4 characters only. To generate bigger passwords, there has to be more loops (pretty obvious in the code below). Happy Brute-forcing !!

    1 #!/bin/bash
    2 
    3 list=`echo {0..9} {a..z} {A..Z}`
    4 
    5 for c1 in $list
    6 do
    7  for c2 in $list
    8  do
    9   for c3 in $list
   10   do
   11    for c4 in $list
   12    do
   13     echo $c1$c2$c3$c4
   14    done
   15   done
   16  done
   17 done
   18