sed - remove nul lines from file
James B. Byrne
byrnejb at harte-lyne.ca
Tue Nov 7 18:54:45 UTC 2017
On Tue, November 7, 2017 13:36, Polytropon wrote:
> On Tue, 7 Nov 2017 12:12:55 -0500, James B. Byrne via
> freebsd-questions wrote:
>> I have a data file created by an ancient proprietary scripting
>> language called QTP. There is a bug in this program which, on
>> occasion, manifests itself by inserting output records consisting
>> entirely of nul (^@) (\x00) bytes at regular intervals. In the
>> present case every 47th. record consists entirely of nuls.
> In this case, awk can also help:
> $ awk '(length > 0)' < infile.txt > outfile.txt
> This will print all lines which are longer than 0 characters.
Thank you very much. This worked exactly as I required.
I infer from this that awk does not consider nul a character and its
presence does not count towards the length of a record. Which is
counter intuitive to me. A nul takes up the same space as any other
character so why is it not counted? I would not have tried this
construction for that reason.
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