I entered a command and it erased everything on my dock.

I entered a command, because some website said it would reset my launchpad to factory settings. Once I did that, the dock was removed off the screen, and it started to violently blink a grey color on my background. My screen shows my background with no dock, and only the top status bar, and then it flashes grey, then flashes back. Please tell me what I can do to help. Also, I think it deleted my dock folder in the Application Support folder. This is the command I used:

sqlite3 ~/Library/Application\ Support/Dock/*.db "DELETE from apps; \

DELETE from groups WHERE title<>''; DELETE from items WHERE rowid>2;" \

&& killall Dock