#!/bin/bash
read -t 10 -p "please input two number ": a b
expr $a + $b> /dev/null
if [ $? -ne 0 ];then
echo "please input zhengshu"
else
echo "$a+$b=$(($a+$b))"
echo "$a-$b=$(($a-$b))"
echo "$a/$b=$(($a/$b))"
echo "$a*$b=$(($a*$b))"
fi
#!/bin/bash
read -t 10 -p "please input two number ": a b
expr $a + $b> /dev/null
if [ $? -ne 0 ];then
echo "please input zhengshu"
else
echo "$a+$b=$(($a+$b))"
echo "$a-$b=$(($a-$b))"
echo "$a/$b=$(($a/$b))"
echo "$a*$b=$(($a*$b))"
fi