NUL character and ANSI-C quoting

Question

I'm attempting to send a binary string to a program using ANSI-C quoted strings. This works fine:

echo $'\x23\x51\x66\x39\x01\x5f\x2f' | cat -v # output: #Qf9^A_/

However, if I have a NUL character (ASCII code 0) in the data, it terminates the string:

echo $'\x23\x00\x66\x39\x01\x5f\x2f' | cat -v # output: #

I'm aware that strings in the C language are null-terminated so I'm guessing a similar constraint applies to this quoting method.

Is there a way I can send ASCII 0 to my program?

doneal24 · Accepted Answer · 2021-11-01 20:33:02Z

1

Try using printf instead of echo.

$ printf "\x23\x00\x66\x39\x01\x5f\x2f" | od -c 0000000 # \0 f 9 001 _ /

answered Nov 1, 2021 at 20:33

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