Actually, i did a mistake. I install tweaks for elementary and then I remove dock and one more from the startup(in tweaks settings). Everything works fine but when I restart only wallpaper is visible there is no dock and top bar in elementary Loki. I can now access the only terminal using Ctrl - Alt + T
Let me see if I can get this answered while not in front of my elementary OS install. I should be able to!
Since you are able to open terminal, great! So, open a terminal and run the command to open System Settings:
Once you open Switchboard, you should be able to access elementary Tweaks. You can then open Tweaks and add both Plank and Wingpanel to the Cerbere section. On the bottom right corner of Tweaks there is a button labeled "Reset to Defaults" and clicking it should add Wingpanel and Plank.
If not, you can manually add them using the "+" symbol. I believe Wingpanel can be added simply using wingpanel as the command and Plank can be added using plank as the command if they are not in a pull-down list. After you've done the above reboot using:
Once you've rebooted and logged in, all should be good. Again, I'm posting this from memory but I think this is it.