#!/bin/bash

input=$1
random_string=`cat /dev/urandom | tr -dc A-Z0-9a-z | head -c 15`

bail()
{
   echo "$1"
   exit 1
}

[[ "$input" == "" ]] && bail "Usage: az [filename]"
[[ -w $input ]] || bail "Error: $input is not writable" 
[[ ! -e $input.tmp ]] && cp $input $input.$random_string || bail "Error: cannot back up $input - $input.$random_string already exists"
sort $input.$random_string > $input || bail "Error: cannot write to $input"
[[ -w $input.$random_string ]] && rm -f $input.$random_string

exit 0