Bug while checking for symbols inside of a string?

I’m creating a small calculator script and I’ve got stumbled on a strange bug. Everything seems to work but not when I input anything starting with (. When I do that if gives false and the code inside of else executes. I’ve tried a lot of ways rewriting how should "$input" =~ [-,+,*,/,(,)] look like but nothing worked. Do you have any idea why that’s happening and how to solve this bug?

#!/bin/bash
read -p "Input: " input
if [[ ! "$input" =~ ^[A-Za-z_]+$ && "$input" =~ ^[0-9] && "$input" =~ [-,+,*,/,(,)] ]]; then
 (echo $input = $(($input))) 2>- || echo "Please, do not input ..."
else
 echo "Please, do not input letters or other special symbols and type in only expressions."
fi

JavaScript
​x
 
#!/bin/bashread -p "Input: " inputif [[ ! "$input" =~ ^[A-Za-z_]+$ && "$input" =~ ^[0-9] && "$input" =~ [-,+,*,/,(,)] ]]; then (echo $input = $(($input))) 2>- || echo "Please, do not input ..."else echo "Please, do not input letters or other special symbols and type in only expressions."fi​

Answer

If you need to make sure your input consists of just certain characters, use this much simpler regex:

#!/bin/bash

read -r -p "Input: " input

if [[ $input =~ ^[0-9+*/()-]*$ ]]; then
   (echo "$input = $((input))") 2> /dev/null || echo "Please, do not input ..."
else
   echo "Please, do not input letters or other special symbols and type in only expressions."
fi

JavaScript
 
#!/bin/bash​read -r -p "Input: " input​if [[ $input =~ ^[0-9+*/()-]*$ ]]; then   (echo "$input = $((input))") 2> /dev/null || echo "Please, do not input ..."else   echo "Please, do not input letters or other special symbols and type in only expressions."fi​

Advertisement

Answer