#!/bin/bash

# change this to whatever extension you'd like to handle
ext=".tar.gz"

# flags to pass to tar
flg="-zxvf"

######################################

`wget $1`

file=`ls -t *$ext | grep -i -m 1 "^.*$ext$"`

if [[ -n $file ]]
then
    tar $flg $file
    unlink $file
else
    echo "Could not find the downloaded file."
fi