how to detect hack attempts.

[home user]

(F-30; Gnome; stand-alone home workstation)

Sometime last year, I saw an article that talked about a tool that 
quickly and easily shows attempts to hack in to a computer.  I think it 
was either in the Fedora magazine or Gnome's website.  I've since made 
multiple attempts to find that article, but failed.  I'm needing to 
check for hack-in attempts (something I suppose I should do 
quazi-periodically anyway). What is the tool/application to do that?  If 
such a tool/application does not exist, then what is the best way for me 
to do that?

thanks,
Bill.