On 3/06/22 07:17, Greg Wooledge wrote:
On Thu, Jun 02, 2022 at 03:12:23PM -0400, duh wrote:
> > Jim Popovitch wrote on 28/05/2022 21:40:
> > > 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?
$cat -n /var/log/syslog | grep warn
and it found "warn" in the syslog file and provided line numbers. I have
not used the -f option
You're getting the line numbers from the log file. The OP wanted the line
numbers of the patterns in the -f pattern file.
Why? I have no idea. There is no standard option to do this, because
it's not a common requirement. That's why I wrote one from scratch
in perl.
I don't know what the OP's use case is, but here's an example I might use:
I have a bunch of custom ignore files for logcheck. After a software
upgrade, I might want to check which patterns no longer match anything,
and can be deleted or modified.
I'd really still want to check with real egrep, though, rather than
using perl's re engine instead.
Cheers,
Richard
