Re: grep: show matching line from pattern file

[David Wright <deblis@lionunicorn.co.uk>]

On Sun 29 May 2022 at 15:02:35 (+0200), Jörg-Volker Peetz wrote:
> Jim Popovitch wrote on 28/05/2022 21:40:
> > Not exactly Debian specific, but hoping that someone here can help.
> > 
> > I have a file of regex patterns and I use grep like so:
> > 
> >     ~$ grep -f patterns.txt /var/log/syslog
> > 
> > What I'd like to get is a listing of all lines, specifically the line
> > numbers of the regexps in patterns.txt, that match entries in
> > /var/log/syslog.   Is there a way to do this?
> 
> How about this:
> 
> $ grep -of patterns.txt /var/log/syslog.1 | grep -n -f - patterns.txt

That will only work for literal patterns, not regex ones.

Cheers,
David.