Three problems with Ubuntu 20.04 under Windows WSL

Question

When using 'gcc' -Os option not accepted

sleep command produces sleep: cannot read realtime clock

Can no longer perform:

sudo cat XXX >> YYY

Results in Permission denied where XXX and YYY are owned by root

Answer 1

Under Ubuntu 20.04 gcc -Os for optimize for size does not work am using gcc -s

and cat issue has been fixed with cat AAA | sudo tee -a BBB >/dev/null

And the shell 'sleep' command not working on WSL turned out to be a 'libc' issue.