hyc@symas.com writes:

I can't think of a grep regex that will detect 8-bit characters, but you need to find them all and get rid of them.

grep -v '[^ -~<tab>]'

where you type ^V tab to the shell to get the <tab>.

To search for probably-UTF-8 chars:

perl -ne '/[\300-\377][\200-\277]/ && print "$ARGV:$_"'

To search for probably-not-UTF-8 8-bit chars:

perl -ne '/[\300-\377](?![\200-\277])|(^|[^\200-\377])[\200-\277]/ && print "$ARGV:$_"'