requires a keypress

# When I run the line: tr -dc '1-6' < /dev/urandom | head -c 1
# from a command prompt in Ubuntu 10.04, it works fine.
# When I run it in the script below, nothing is displayed, and the script does not end
# until I press any key. This keystroke is then echoed at the beginning of the next command prompt.
####### script begins below #######
#!/bin/bash
SLPTIME=`tr -dc '1-6' < /dev/urandom | head -c 1`
echo $SLPTIME