examples/scripts/hanoi.bash

   1 # Towers of Hanoi in bash
   2 #
   3 # cribbed from the ksh93 book, example from exercises on page 85
   4 #
   5 # Chet Ramey
   6 # chet@po.cwru.edu
   7
   8 hanoi() # n from to spare
   9 {
  10     typeset -i nm1=$1-1
  11     ((nm1>0)) && hanoi $nm1 $2 $4 $3
  12     echo "Move disc $2 to $3"
  13     ((nm1>0)) && hanoi $nm1 $4 $3 $2
  14 }
  15
  16 case $1 in
  17 [1-9])
  18       hanoi $1 1 2 3;;
  19 *)    echo "${0##*/}: Argument must be from 1 to 9"
  20       exit 1;;
  21 esac