Reporting on application usage is an interesting topic on the Mac. This is done automatically with a number of device management solutions. But there are things built into the OS that can help as well.
mdls "/Applications/Xcode.app" -name kMDItemLastUsedDate | awk '{print $3}'
Now, if you happen to also need the time, simply add ,$4 to the end of your awk print so you can see the next position, which is the time.
Additionally, a simple one-liner to grab the foreground app via AppleScript is:
osascript -e 'tell application "System Events"' -e 'set frontApp to name of first application process whose frontmost is true' -e 'end tell'
That’s pretty much all I had to say about that.
