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From: Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups: comp.lang.awk
Subject: Re: Can I output a binary file from an AWK program?
Date: Sun, 29 Mar 2026 17:07:30 -0700
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Kaz Kylheku <046-301-5902@kylheku.com> writes:
> On 2026-03-28, Alan Mackenzie <acm@muc.de> wrote:
>> I think the Subject: line says it all.  I have a text source file to
>> convert into a binary output file.  For example, I want to be able to
>> output a 32-bit integer as a four byte little-endian binary integer.
>
> Firstly, Awk's printf has a %c specifier which will output any byte:
>
> $ awk 'BEGIN { printf("%c%c", 0x41, 0x0A) }'
> A
> $
[...]

The behavior seems to depend on the current locale.  I haven't
investigated it thoroughly.  I don't know whether there's a way to
force binary output.

For example, the cent sign '¢' is U+00a2, represented in UTF-8
as the two-byte sequence 0xc2, 0xa2.

I have LANG=en_US.UTF-8 in my environment.

$ gawk --version | head -n 1
GNU Awk 5.2.1, API 3.2, PMA Avon 8-g1, (GNU MPFR 4.2.1, GNU MP 6.3.0)
$ gawk 'BEGIN { printf("%c\n", 0xa2) }'
¢
$ LANG=C gawk 'BEGIN { printf("%c\n", 0xa2) }' | hd
00000000  a2 0a                                             |..|
00000002
$

(I filtered the last through hd because the output is not valid UTF-8.)

nawk behaves similarly.  mawk and busybox awk do not.

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */