Question

I have written a RegEx for password which takes any character with min length of 5 and maximum length of 30.

I’ve tried the following expression:

(\S){5,30}

but it also accepts passwords with more than 30 characters. How can I make sure it doesn’t match such passwords?

Answer 1

Your problem is that your regex also matches substrings of your input.

\S{5} (or (\S){5}) matches 12345 in the string 1234567890.

So you need to anchor your regex:

^\S{5,30}$

validates a 5-30 character, non-whitespace string. The parentheses around \S are useless and unnecessary.

At any rate, why would you impose a length restriction on a password? And why wouldn’t you allow whitespace characters in it? See also this.