Bash Script Question

[Linda]

It has been 20 years since I did shell scripting. I was wondering if 
anyone could help me out so I didn't have to find my old reference manuals.

I have the following bash shell script

#!/bin/bash
# print.sh
# print files from the right-click context menu in Nautilus
#place this script in ~/.gnome2/nautilus-scripts

# uses the default print
echo "$NAUTILUS_SCRIPT_SELECTED_FILE_PATHS" | while
read file
    do
         lpr "$file"
done
exit


I would like to change it so it only prints pdf, ps and txt files will 
this work.

echo "$NAUTILUS_SCRIPT_SELECTED_FILE_PATHS" | while
read file
   
case "$file" in
  '*.pdf ' | ''*.PDF')
  '*.ps ' | ''*.PS')
  '*.txt ' | ''*.TXT') lpr "$file"
                              ;;
  esac
exit

Would this work so no one tries to print an open office file or other 
such thing with the script?
I'm sure there is a prettier way to do it.

                Linda