shell中的整数和浮点数运算

整数运算

num=`expr 2 + 2`
echo "$num"
结果: 4

a=55
b=45
echo `expr $a + $b`
结果: 100

浮点数运算

if [ `echo "1.05 < 1.001" | bc` -eq 1 ];then echo "OK"; else echo "NO"; fi

if [ `echo 6.354 > 6.353|bc` -eq 1 ]
then
	x='ok'
else
	x='on'
fi

while [ $x == 'ok' ]
do
	for f in {1..10}
		do
			echo "$f"
		done
	break
done