shell脚本检查输入是否是字符串/整数/浮点

Question

#!/bin/bash

read -p "Enter value:" val

echo "$val"|grep "^[0-9]*$"
val="$?"

if [[ $val == 0 ]]
then
echo "Integer"
exit
fi

echo $val|grep "^[a-zA-Z]*$"

val="$?"

if [[ $val == 0 ]]
then
echo "String"
exit
fi


echo $val|grep "^[0-9]*.[0-9]*$"

val="$?"

if [[ $val == 0 ]]
then
echo "Float"
exit
fi

如果我输入像“ape”这样的字符串，它会显示“grep invalid range”，然后打印浮点数。我哪里做错了？

Answer 1

此 bash 代码为整数（如 123）返回整数，为浮点数（如 123.4）返回浮点数，为任何其他输入值（如“123”、One23 123. 或 123.4.5）返回字符串。

#!/bin/bash
read -p "Type a number or a string: " input
if [[ $input =~ ^[+-]?[0-9]+$ ]]; then
echo "Input is an integer."

elif [[ $input =~ ^[+-]?[0-9]+\.$ ]]; then
echo "Input is a string."

elif [[ $input =~ ^[+-]?[0-9]+\.?[0-9]*$ ]]; then
echo "Input is a float."

else
echo "Input is a string."
fi