GNU bug report logs - #65416
Feature request: include first line of file in output

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Package: grep;

Reported by: Daniel Green <ddgreen <at> gmail.com>

Date: Mon, 21 Aug 2023 07:16:02 UTC

Severity: wishlist

Done: Paul Eggert <eggert <at> cs.ucla.edu>

Bug is archived. No further changes may be made.

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Message #29 received at 65416 <at> debbugs.gnu.org (full text, mbox):

From: "Paul Jackson" <pj <at> usa.net>
To: "Daniel Green" <ddgreen <at> gmail.com>, arnold <at> skeeve.com
Cc: 65416 <at> debbugs.gnu.org
Subject: Re: bug#65416: Feature request: include first line of file in output
Date: Wed, 23 Aug 2023 03:20:26 -0500

sed and awk can also to this (1st line plus any matching lines)

Following transcript from zsh session on my fast Ryzen:

$ <<-'@@' time sh -c "grep -m1 USER && grep carenas"
USER,TIP
john,0
jane,10
carenas,100
@@
USER,TIP
carenas,100
sh -c "grep -m1 USER && grep carenas"  0.00s user 0.00s system 93% cpu 0.003 total

$ <<-'@@' time sed -n -e 1p -e /carenas/p
USER,TIP
john,0
jane,10
carenas,100
@@
USER,TIP
carenas,100
sed -n -e 1p -e /carenas/p  0.00s user 0.00s system 80% cpu 0.001 total

$ <<-'@@' time awk 'NR == 1 || /carenas/'
USER,TIP
john,0
jane,10
carenas,100
@@
USER,TIP
carenas,100
awk 'NR == 1 || /carenas/'  0.00s user 0.00s system 88% cpu 0.002 total

As I expected, sed is fastest, grep next, and awk slowest of the three,
but the 1, 2, and 3 millisecond totals are within the margin of test error.

-- 
                Paul Jackson
                pj <at> usa.net
This bug report was last modified 1 year and 322 days ago.

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