Подставить переменную в переменную

#!/bin/bash
weather_icon="temp.xbm"
temp_variable="weather"

temp="${temp_variable}_icon"

c=${!temp}
echo $c

network_icon="^i($HOME/.xmonad/bitmap/wired.xbm)"
packages_icon="^i($HOME/.xmonad/bitmap/pacman.xbm)"
rss_icon="^i($HOME/.xmonad/bitmap/dish.xbm)"
mail_icon="^i($HOME/.xmonad/bitmap/mail.xbm)"
weather_icon="^i($HOME/.xmonad/bitmap/temp.xbm"
date_icon="^i($HOME/.xmonad/bitmap/date.xbm)"
clock_icon="^i($HOME/.xmonad/bitmap/clock.xbm)"

#net_lock
if [ -f "/tmp/network_status" ] 
then
  network="${color_sec1}${network_icon} ${color_main}`cat /tmp/network_status`  "
else
  network=""
fi

#packages
if [ -f "/tmp/packages_status" ] 
then
  packages="${color_sec1}${packages_icon} ${color_main}`cat /tmp/packages_status`  "
else
  packages=""
fi

#rss
if [ -f "/tmp/rss_status" ] 
then
  rss="${color_sec1}${rss_icon} ${color_main}`cat /tmp/rss_status`  "
else
  rss=""
fi

#mail
if [ -f "/tmp/gmail_status" ] 
then
  mail="${color_sec1}${mail_icon} ${color_main}`cat /tmp/gmail_status`  "
else
  mail=""
fi


#weather
if [ -f "/tmp/weather_status" ]
then
  weather="${color_sec1}${weather_icon} ${color_main}`cat /tmp/weather_status`°C  "
else
  weather=""
fi

icon_path="$HOME/.xmonad/bitmap"
weather_icon="temp.xbm"

function ifexist {
if [ -f /tmp/${1}_status ]
then
  temp="${1}_icon"
  icon="^i($icon_path/${!temp})"  
  echo "${color_sec1}${icon} ${color_main}$(cat /tmp/${1}_status)"
else
  echo ""
fi
}

weather="$(ifexist weather)°C  "

eval new_var="\$${temp_variable}"     
new_var="${new_var}_icon"
echo $new_var