Mattyboy,

Your question sounds like homework as do your other posts. Please read the forum rules.

As for an example of setting an extended ACL:

/usr/bin/setfacl -s user:user4991:r-x,user::rwx,group::---,mask:r-x,other:---, /path/to/some/file

Read the manpage for setfacl.

Cheers,

Keith