How did my Mac end up with iPhone 4S as my host name in the user prompt in OS X terminal? The other day I was searching for Xcode iOS 5 tutorials. About a day or two later, I noticed my terminal prompt is now "iPhone4s : myusername". Naturally , my biggest fear is that there could be a worm or trojan horse on here. I look up the current procedure for checking the most current Mac Malware and the system turned up clean. I followed the examples to edit the PIF with the code:

PS1="\h : \u\$" 


and it does not get rid of the "iPhone4s" prefix. I checked the System Preferences > Sharing and the name for the computer is correct.

How do I go about making sure the system is not hacked, and how to get rid of the iPhone4s name? I have 3 accounts created on this system. The other 2 are not affected.
It turns out it was just as our Unix guy had said.  The iPhone4s Host name is only present when I am at work and my mac book is accessing the companies wireless network. When I am away, the terminal shows the proper hostname. We are a mac centric company but we use all windows servers. Apparently, that makes a situation ripe for these strange DHCP anomalies.

Thanks for the help.