Question

I got this issue figuring out how to build a regexp for verifying a netbios name. According to the ms standard these characters are illegal
\/:*?”<>|

So, thats what I’m trying to detect. My regex is looking like this

^[\\\/:\*\?"\<\>\|]$

But, that wont work.

Can anyone point me in the right direction? (not regexlib.com please…)
And if it matters, I’m using php with preg_match.

Thanks

Answer 1

Your regular expression has two problems:

1. you insist that the match should span the entire string. As Andrzej says, you are only matching strings of length 1.
2. you are quoting too many characters. In a character class (i.e. []), you only need to quote characters that are special within character classes, i.e. hyphen, square bracket, backslash.

The following call works for me:

preg_match('/[\\/:*?"<>|]/', "foo");  /* gives 0: does not include invalid characters */
preg_match('/[\\/:*?"<>|]/', "f<oo"); /* gives 1: does include invalid characters */