you can't run commands like grep but you can run nano and there are the user names in the '?' help menu.
/etc/lshell.conf to make changes. Not sure if they get reset on update though.
I looked there and yes, we can add grep but the users being listed there seems like a limited shell bug.
Indeed, you are welcome to add whatever commands to lshell you see fit as we only write lshell.conf a single time: during installation.