If you have to work with the text file then I would recommend using sed instead of perl. 
# If your version of sed supports editing in place
sed -i -e '/^00020123837$/d' somefile.txt

#Otherwise
sed -e '/^00020123837$/d' somefile.txt > tmp.txt
mv tmp.txt somefile.txt

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If this is done regularly or other maintenance work is going to be done then a database becomes a much more attractive option.

In reply to Re: 15 billion row text file and row deletes - Best Practice? by imp
in thread 15 billion row text file and row deletes - Best Practice? by awohld

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