Question

I’m working on a shell script that will be used by others, and may ingest suspect strings. It’s based around awk, so as a basic resiliency measure, I want to have awk output null-terminated strings – the commands that will receive data from awk can thus avoid a certain amount of breakage from strings that contain spaces or not-often-found-in-English characters.

Unfortunately, from the basic awk documentation, I’m not getting how to tell awk to print a string terminated by an ASCII null instead of by a newline. How can I tell awk that I want null-terminated strings?

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Versions of awk that might be used:

[user@server1]$ awk --version
awk version 20070501

[user@server2]$ awk -W version
mawk 1.3.3 Nov 1996, Copyright (C) Michael D. Brennan

[user@server3]$ awk -W version
GNU Awk 3.1.7

So pretty much the whole family of awk versions. If we have to consolidate on a version, it’ll probably be GNU Awk, but answers for all versions are welcome since I might have to make it work across all of these awks. Oh, legacy scripts.

Answer 1

Alright, I’ve got it.

awk '{printf "%s\0", $0}'

Or, using ORS,

awk -vORS=$'\0' //