Subject: Re: bug#44409: Example in manual no longer works

From: 積丹尼 Dan Jacobson <[email-masked]>
Date: Wed, 04 Nov 2020 07:32:42 +0800

>>>>> "EZ" == Eli Zaretskii <[email-masked]> writes:

EZ> The example in the manual doesn't mention /etc/motd of any other binary file.  It uses text files, where this issue doesn't exist.

Since when is /etc/motd a binary file?

If it were a binary file, the first grep,

>> $ grep --color -nH --null -e a /etc/motd
>> /etc/motd:2:The programs included with the Debian GNU/Linux system are free software;
>> /etc/motd:3:the exact distribution terms for each program are
>> described in the...

would fail.

But it doesn't. Only the second grep fails:

>> $ grep --color -nH --null -e a /etc/motd | grep x
>> Binary file (standard input) matches

So we see the issue indeed exists with text files!!

Double proof:

$ file /etc/motd
/etc/motd: ASCII text

Thus we see that one cannot simply slap

 "| grep bar | grep toto"

onto the end of a working grep command anymore!

Back when the manual was written, one could. But not anymore.

EZ> Yes, but you need to edit that prompt anyway in order to type the
EZ> command with a pipe, so the original prompt doesn't matter much.

No!

In the past one could simply slap the pipe(s) on to the back.

Now that no longer works.

Therefore the example needs to be rewritten to make it work again.

(Or specific instructions need to be given: "Be sure to remove any
'--null' that emacs has stuck in, for this example to work.")