Linux Admin 3: logical constructs

if-then: if-then allows you to make decisions

if [ $USER == "jeremy" ]; then
echo "Hi Jeremy"
fi

string tests: ==
math tests: -eq -lt -gt -le -ge
[ ] is a simple test
[[ ]] is the extended test:

HOSTNAME=$(/bin/hostname)
if [[ $USER == "jeremy" && $HOSTNAME == "wittgenstein" ]]; then
	echo "warning, jeremy, you are working on production host wittgenstein"
	echo "please be careful with sudo on this box"
fi

note the fi
if - then - elif - fi

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