DECISION-MAKING & LOOP CONSTRUCTS:
* Shell programs can perform conditional tests on their arguments and variables and execute different commands based on the results. For example:
if [ "$1" = "hyena" ]
then
echo "Sorry, hyenas not allowed."
exit
elif [ "$1" = "jackal" ]
then
echo "Jackals not welcome."
exit
else
echo "Welcome to Bongo Congo."
fi
echo "Do you have anything to declare?"
-- checks the command line to see if the first argument is "hyena" or "jackal" and bails out, using...