[tatref]

Isn't simpler to use perl?

Perl -pe 's/.(capture this)./$1/'

That way, you can capture multiple groups, and change the format in the output. You can also do simple calculations if you capture numbers

[tryauuum]

for me no, anything perl-related is not simple

I also tried putting this question in GPT3:

> Isn't simpler to use perl?

> It is simpler to use Perl, but it is not as efficient as using C or C++.

[jraph]

Nice one, I'll try to counter this garbage GPT3 answer:

- I don't think the regex engine in Perl is implemented in Perl. It's probably implemented in C/C++, like grep. libpcre is in C anyway.

- Even if grep is/were more efficient, You might have consumed more time and energy thinking, typing and running "grep --only-matching --perl-regexp 'prefix \K\d+(?= suffix)'" than the suggested perl solution

- I might have consumed even more energy typing this reply. My computer is there, waiting for me typing, doing not much.

[melagonster]

grep have perl regex mode.