Subject: Re: bug#63962: possible error in the grep program

From: Paul Eggert <[email-masked]>
Date: Thu, 8 Jun 2023 14:07:16 -0700

On 6/8/23 04:27, Василий Алексеенко wrote:

> 1) The initial list of IP addresses in the file is formed start_list.txt .
> 
> 2) Must be removed from the list start_list.txt IP addresses using a
> larger file exclude_list.txt
> 
> grep -vF --file=exclude_list.txt start_list.txt > list_grep.txt

The line '10.0.23.4' in exclude_list.txt matches the line '10.0.23.48' 
in start_list.text. That is, the first line is a substring of the second 
line. So this usage of 'grep' doesn't do what you want.

To get the effect you want, also use the -x option. E.g.:

grep -vxF -f exclude_list.txt start_list.txt