Few will deny that many people that use Unix-like Operating Systems or M$ Windows make the switch to Ubuntu these days or are considering it. The following links will show you Ubuntu equivalents of many traditional Unix applications, and tasks.
SwitchingToUbuntu/FromLinux
Switching to Ubuntu From Red Hat Enterprise Linux And Fedora
FromGentooToKubuntu
Switching to Ubuntu From Mac OS X
SwitchingToUbuntu/FromWindows