shell中read的使用

read [参数][变量名]

read -p "please input a number:"var

read -t 10 -p "please input a number:"var

#!/bin/sh

while true

do

read -t 10 -p "please input two number:" a b

expr $a + 0 >/dev/null 2>&1

[ $? -ne 0 ] && continue

expr $b + 0 >/dev/null 2>&1

[ $? -ne 0 ] && continue||break

done

echo "a-b =$(( $a - $b ))"

echo "a+b =$(( $a + $b ))"

echo "a*b =$(( $a * $b ))"

echo "a/b =$(( $a / $b ))"

echo "a**b =$(( $a ** $b ))"

echo "a%b =$(( $a % $b ))"

传参：

[root@www shell]# cat read1.sh

#!/bin/sh

a="$1"

b="$2"

Usage(){

echo "Usage:sh $0 num1 num2"

exit 1

}

if [ $# -ne 2 ];then

Usage

fi

expr $a + 0 >/dev/null 2>&1

[ $? -ne 0 ] && Usage

expr $b + 0 >/dev/null 2>&1

[ $? -ne 0 ] && Usage

echo "a-b =$(( $a - $b ))"

echo "a+b =$(( $a + $b ))"

echo "a*b =$(( $a * $b ))"

echo "a/b =$(( $a / $b ))"

echo "a**b =$(( $a ** $b ))"

echo "a%b =$(( $a % $b ))"