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I'm attempting to extract the contents of some files by alphabetical (which in this case also means date and iteration) order and when I test the process first with ls:

$ find /opt/minecraft/wonders/logs/ -name 20* -type f -mtime -3 -print0 \
   | sort | xargs -r0 ls -l | awk -F' ' '{print $6 " " $7 " " $9}'

I get a positive result:

Aug 18 /opt/minecraft/wonders/logs/2018-08-17-3.log.gz
Aug 18 /opt/minecraft/wonders/logs/2018-08-18-1.log.gz
Aug 19 /opt/minecraft/wonders/logs/2018-08-18-2.log.gz
Aug 19 /opt/minecraft/wonders/logs/2018-08-19-1.log.gz
Aug 20 /opt/minecraft/wonders/logs/2018-08-19-2.log.gz
Aug 20 /opt/minecraft/wonders/logs/2018-08-20-1.log.gz

However, when I go to actually extract the files the sort order is lost:

$ find /opt/minecraft/wonders/logs/ -name 20* -type f -mtime -3 -print0 \
   | sort | xargs -r0 gunzip -vc | grep "\/opt.*"`

/opt/minecraft/wonders/logs/2018-08-18-1.log.gz:     66.8%
/opt/minecraft/wonders/logs/2018-08-18-2.log.gz:     83.1%
/opt/minecraft/wonders/logs/2018-08-19-1.log.gz:     70.3%
/opt/minecraft/wonders/logs/2018-08-19-2.log.gz:     72.9%
/opt/minecraft/wonders/logs/2018-08-20-1.log.gz:     73.3%
/opt/minecraft/wonders/logs/2018-08-17-3.log.gz:     90.2%

How can I maintain the sort order while unzipping these files?

slm
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Jesse Yishai
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1 Answers1

8

You have used the -print0 option with find, and -0 with xargs, but you forgot to use -z for sort, so sort essentially sees a single line (unless your filenames contain \n). The output you see with ls is probably ls doing some sorting.

find /opt/minecraft/wonders/logs/ -name '20*' -type f -mtime -3 -print0 |
  sort -z | xargs -r0 gunzip -vc | grep /opt

(Note: 20* is a glob and needs to be quoted for the shell so it's passed literally to find, you don't want to escape / for grep, what that does is unspecified, no need for .* at the end of the regexp if all you want is print the matching line)

Stéphane Chazelas
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muru
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    @JesseYishai If the answer helped you, don't forget to mark the answer as accepted by clicking on the check mark beside the answer ! :) – Ikaros Aug 21 '18 at 08:29