(grep) Regex to match non-ASCII characters?

Question

On Linux, I have a directory with lots of files. Some of them have non-ASCII characters, but they are all valid UTF-8. One program has a bug that prevents it working with non-ASCII filenames, and I have to find out how many are affected. I was going to do this with find and then do a grep to print the non-ASCII characters, and then do a wc -l to find the number. It doesn't have to be grep; I can use any standard Unix regular expression, like Perl, sed, AWK, etc.

However, is there a regular expression for 'any character that's not an ASCII character'?

Answer 1

This will match a single non-ASCII character:

[^\x00-\x7F] 

This is a valid PCRE (Perl-Compatible Regular Expression).

You can also use the POSIX shorthands:

• [[:ascii:]] - matches a single ASCII char
• [^[:ascii:]] - matches a single non-ASCII char

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[^[:print:]] will probably suffice for you.**

Answer 2

No, [^\x20-\x7E] is not ASCII.

This is real ASCII:

 [^\x00-\x7F] 

Otherwise, it will trim out newlines and other special characters that are part of the ASCII table!