#!/bin/sh
# Copyright 2005 Daniel Cer (daniel.cer@cs.colorado.edu)
#
# This work is licensed under the Creative Commons Attribution-NonCommercial-
# ShareAlike License. To view a copy of this license, visit 
# http://creativecommons.org/licenses/by-nc-sa/2.5/ or send a letter to 
# Creative Commons, 543 Howard Street, 5th Floor, San Francisco, California, 
# 94105, USA.

# bubble_sort - sorts the array referenced by the first argument to this 
# function. 
#
# e.g. to sort an array '$entries[@]', the following statement would be 
# used: bubble_sort entries
function bubble_sort {
  local entries_ref=$1
  local i j entries_N val_j val_j_inc

  eval entries_N=\${#$entries_ref[@]}
  for i in `seq $[entries_N-1] -1 0`; do
    for j in `seq 0 $[i-1]`; do
      eval val_j=\${$entries_ref[$j]}
      eval val_j_inc=\${$entries_ref[$[j+1]]}
      if [ `bc<<<"$val_j_inc < $val_j"` -eq 1 ]; then
        eval $entries_ref[$j]=$val_j_inc
        eval $entries_ref[$[$j+1]]=$val_j
      fi
    done
  done
}

if [ $# -ne 1 ]; then
  echo -e "Usage:\n\t$0 (file with numbers to sort)" >&2
  exit -1
fi

# read in the items
exec 3<$1
while read -u 3 entry; do entries[${#entries[@]}]=$entry; done
3>&-

# sort them
bubble_sort entries

# display the sorted results
for entry in ${entries[@]}; do echo $entry; done