Advanced Bash−Scripting Guide

Advanced Bash−Scripting Guide
done
echo "Random number between $FLOOR and $RANGE −−− $number"
echo
# Generate binary choice, that is, "true" or "false" value.
BINARY=2
number=$RANDOM
T=1
let "number %= $BINARY"
# let "number >>= 14" gives a better random distribution
# (right shifts out everything except last binary digit).
if [ "$number" −eq $T ]
then
echo "TRUE"
else
echo "FALSE"
fi
echo
# May generate toss of the dice.
SPOTS=7 # Modulo 7 gives range 0 − 6.
DICE=2
ZERO=0
die1=0
die2=0
# Tosses each die separately, and so gives correct odds.
while [ "$die1" −eq $ZERO ] # Can't have a zero come up.
do
let "die1 = $RANDOM % $SPOTS" # Roll first one.
done
while [ "$die2" −eq $ZERO ]
do
let "die2 = $RANDOM % $SPOTS" # Roll second one.
done
let "throw = $die1 + $die2"
echo "Throw of the dice = $throw"
echo
exit 0
Example 9−24. Picking a random card from a deck
#!/bin/bash
# pick−card.sh
# This is an example of choosing a random element of an array.
# Pick a card, any card.
Suites="Clubs
Chapter 9. Variables Revisited 97