How to check if a string contains a special character (!@#$%^&*()_+)

Question

I was wondering what would be the best way to check if a string as

$str 

contains any of the following characters

!@#$%^&*()_+

I thought of using ASCII values but was a little confused on exactly how that would be implemented.

Or if there is a simpler way to just check the string against the values.

Answer 1

Match it against a glob. You just have to escape the characters that the shell otherwise considers special:

#!/bin/bash
str='some text with @ in it'
if [[ $str == *['!'@#\$%^\&*()_+]* ]]
then
  echo "It contains one of those"
fi

Answer 2

You can also use a regexp:

if [[ $str =~ ['!@#$%^&*()_+'] ]]; then
    echo yes
else
    echo no
fi

Some notes:

• The regexp includes the square brackets
• The regexp must not be quoted (so $str =~ '[!...+]' would not work).
• There is no need to escape chars as is necessary with the glob approach in another answer, because the chars are between the brackets, where they are taken literally by regexp
• as with glob pattern [] means "anything in the contained string"
• because the pattern does not start with ^ or end with $ there will be a match anywhere in the $str.