On Sat, Apr 29, 2023 at 01:52:11AM +0200, coreyh@free.fr wrote:
> $ sudo echo 123 > /root/123.txt
>
> It tells me "permission rejected".
>
> Why this sudo can't get success?
Because the redirection is done by your shell before sudo is executed.
See <https://mywiki.wooledge.org/BashPitfalls#pf53> for suggestions,
but basically you're looking at variants of:
sudo sh -c 'echo 123 > /root/123.txt'