Script to fetch weather data from API

weather.sh

#!/bin/bash

API=

# Set URL for fetching weather information and an Error Msg for invalid input
  URL=http://api.wunderground.com/api/$API/geolookup/conditions/q/CA/Stanford.xml
  ERR="Error: Arguments expected in form [City] [State]. Ex: weather Palo_Alto CA"

  # handles arguments for location / default is Stanford CA
  # well-formed argument example: "weather Memphis TN"
  if [ ! -z "$1" ] && [ ! -z "$2" ]
    then
      URL=${URL/Stanford/$1}
      URL=${URL/CA/$2}
  fi
  
  # Handles erroneous input such as:
  # no second argument or a second argument with invalid State Code
  # bad argument example: "weather Memphis T"
  if [[ ! -z "$1" && -z "$2" ]] || [[ ! -z "$2" && ! ${#2} -eq 2 ]]
    then
      echo "$ERR"
      exit 1
  fi
  
  # get xml file from API, parse out relevant information and echo to stdout
  # NOTE: ~/bin/w.xml~ MUST BE AN EXISTENT FILE!
  curl -s $URL > ~/bin/w.xml~
  if grep -qom1 "<icon_url>" ~/bin/w.xml~; then
      cat ~/bin/w.xml~ > ~/bin/w.xml
  fi