Re: [PATCH mptcp-net v2 4/5] selftests: mptcp: print trailing bytes with od

[Geliang Tang <geliang@kernel.org>]

On Fri, 2025-09-05 at 20:18 +0200, Matthieu Baerts (NGI0) wrote:
> This is better than printing random bytes in the terminal.
> 
> Note Jakub suggested 'hexdump', but Mat found out that this tool is
> not
> often installed by default. 'od' can do a similar job, and it is in
> the
> POSIX specs and available in coreutils, so it should be on more
> systems.
> 
> Suggested-by: Jakub Kicinski <kuba@kernel.org>
> Suggested-by: Mat Martineau <martineau@kernel.org>
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
> ---
> v2: switch to 'od', and no more check for its presence (Mat)
> ---
>  tools/testing/selftests/net/mptcp/mptcp_lib.sh | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/net/mptcp/mptcp_lib.sh
> b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
> index
> 09cd24b2ae466205dacbdf8289eb86c08534c475..d62e653d48b0f2ef7a01e289fa0
> be8907825667d 100644
> --- a/tools/testing/selftests/net/mptcp/mptcp_lib.sh
> +++ b/tools/testing/selftests/net/mptcp/mptcp_lib.sh
> @@ -384,7 +384,7 @@ mptcp_lib_make_file() {
>  mptcp_lib_print_file_err() {
>  	ls -l "${1}" 1>&2
>  	echo "Trailing bytes are: "
> -	tail -c 27 "${1}"
> +	tail -c 32 "${1}" | od -x | head -n2

nit:

It shows more bytes (32) here, but it wasn't mentioned in the commit
log.

Thanks,
-Geliang

>  }
>  
>  # $1: input file ; $2: output file ; $3: what kind of file