Re: say if grep can find non-ascii

[Paul Eggert]

Julian Foad <address@hidden> writes:

> I don't think the Grep manual should say explicitly how to do that
> particular thing.

I disagree.  I think it'd be useful to have a simple pattern that
tests for ASCII characters (i.e., bytes in the range 00 through 7F).

I myself needed such a pattern in the last couple of days, when I
mentioned to Andrew Josey of the Open Group that some of their
published text documents contained non-ASCII characters, and he
responded "How can I easily check for this?".  I ended up telling him
"LC_ALL=C grep '[^[:space:][:print:]]'", which (1) is not quite
correct, and (2) is far less convenient than "grep '[[:ascii:]]'"
would be.

> I'm not sure what the definition of "ASCII" is in this case

The standard one.  See <http://en.wikipedia.org/wiki/ASCII>.

> Does the following command do what you want?
>
>    grep '[ -~]'

That isn't correct, first because it's not portable outside the C
locale, and second because it doesn't match the 33 ASCII control
characters.