Remote Shutdown

I'm pretty much a Newbie when it comes to Linux, so the answer to this question should be pretty simple.

I'm running Redhat 7 on an old PC, since I only have one monitor, I telnet into the linux box using a terminal emulator. Since noone can telnet using the root user, I go across as a user and then su. (I'm not very concerned with security at the moment)

But... if I do this, I cant run the shutdown command - in fact the bash shell doesn't even recognise it as a command, even though I can look it up in the manual.

Is this some kind of security? It means that I need to pull the monitor out of the PC and plug it into the Linux machine just to shut it down  -  something I'd like to do remotely.

Is there a configuration file somewhere or something I can do to permit a remote shutdown?

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