代码: 全选
while [ test "$1" -lt 0 ]
do
read -p "The input is negative or not a integer! Please input again:" integer
done
还有如何在while的条件中比较两个整数的大小呢?
如果还想加上一个判断条件,判断$1是不是一个整数,应当如何编写呢?
本人菜鸟,先谢谢各位了!
代码: 全选
while [ test "$1" -lt 0 ]
do
read -p "The input is negative or not a integer! Please input again:" integer
done
代码: 全选
#!/bin/sh
#Test the number of args, if no then input
if [ $# -lt 1 ]
then
echo 'Please input a positive integer!'
read num
else num=$1
fi
#Doing test
while :
do
#通过expr运算是否成功来测试num是否是int
#输出和错误信息重定向
expr $num + 1 >/dev/null 2>&1
#通过特殊变量?查看上次命令执行状态
if [ $? -eq 0 ]
then
if [ $num -lt 0 ]
then
echo "$num is a negative integer! Please input again:"
read num
continue
else
echo "$num is a legal input"
break
fi
else echo "$num is not a integet,Please input again:"
read num
fi
done
exit 0
代码: 全选
A='14'
echo `expr $A + 2`
代码: 全选
read -p "Please input again:" integer
while [[ -n "$integer" && -z "${integer//[0-9]}" && "$integer" -gt 0 ]]
do
read -p "The input is negative or not a integer\! Please input again:" integer
done
代码: 全选
read -p "Please input again:" integer
while expr "$integer" : "^[1-9][0-9]*$" >& /dev/null
do
read -p "The input is negative or not a integer\! Please input again:" integer
done