Re: use of awk instead of complex multielement commands (was Re: 'grep -o -m' (was Re: Can't mount CD image of Win95 game))
On Tue, 20 Dec 2022 at 22:04, David <bouncingcats@gmail.com> wrote:
> On Tue, 20 Dec 2022 at 22:02, David <bouncingcats@gmail.com> wrote:
> > $ echo -e '100:CD001\n200:CD001' | awk 'BEGIN { FS=":" } /CD001/ &&
> > NR==1 { print $1 - 50 }'
> > 50
>
> Oops, my mistake, that's not the solution. Give me another minute and I
> will post a better one one.
The below does a better job:
(command should be all on one line)
$ echo -e '100:CD001\nXXX\n200:CD001' | awk 'BEGIN { FS=":" ; done=0 }
/CD001/ && done==0 { print $1 - 50 ; done=1 }'
50
Still quite clean and obvious for a one liner (for folks who know how 'awk'
works), and it will be significantly faster than pipelines and
subshell collections.
Not that that is always important. But I just commented today
because so often 'awk' is ignored as if its only capability is 'print $1'
when in fact it is actually very powerful but neglected.
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