结构化命令

if [ condition ]; then

elif [ condition ]; then

else [ condition ]
fi

if [ condition1 ] && [ condition2 ]; then
fi

if [ condition1 ] || [ condition2 ]; then
fi

case var in
pattern1 | pattern2) command1;;
pattern3) command2;;
*) command3;;
esac

for var in list
do
command
done

while [ condition ]
do

done

until []
do

done