That works, as well as the Perl version I've been using:

perl -ne 'print if ($. == 1 || /pattern/)'

But timings for a real-life example (3GB file with ~16m lines, CentOS 7) show the problem:

grep (v2.20): ~1.15s

perl (v5.36.1): ~4.48s

awk (v4.0.2): ~10.81s

Admittedly grep is just searching in those timings, but I suspect it could accomplish the full task with a minimal decrease in speed.

Dan

On Mon, Aug 21, 2023 at 12:57 PM <arnold@skeeve.com> wrote:

Daniel Green <ddgreen@gmail.com> wrote:

> I'm frequently searching CSV files with 20-30 columns, and when there's a
> hit it can be hard to know what the columns are. An option to also print
> the first line of a file (either always, or only if that file had a match
> to the pattern) in addition to any hits would be nice.
>
> Thanks,
> Dan

It sounds like awk would be a better tool:

awk 'FNR == 1 || /pattern/' files ...

should do the trick.

HTH,

Arnold