linux shell script如何判断read命令取得的用户数据长度小于等于4，且为数字？

Posted 2023-03-20

#!/bin/bash

echo "Please enter: \c"
read INPUT

if [ $#INPUT -eq 4 -a "$INPUT//[0-9]/" = "" ]
then
echo "$INPUT len 4 and all digits"
else
echo "invalid input"
fi 参考技术A #!/bin/sh
read -p "Input a number: " var

# Check if input is a number
expr "$var" + 10 >/dev/null 2>&1
if [ $? -ne 0 ]; then
echo -e "Wrong input!\nMust input a number!"
exit 1
fi

# Check data length if <=4
echo $var|egrep '[0-9]\1,4\' >/dev/null 2>&1
if [ $? -ne 0 ]; then
echo -e "Wrong input!\nData length should be no greater than 4!"
exit 1
fi

echo $var
exit 0 参考技术B #!/bin/bash echo "Please enter: \c" read INPUT if [ $#INPUT -eq 4 -a "$INPUT//[0-9]/" = "" ] then echo "$INPUT len 4 and all digits" else echo "invalid input" fi~