Ubuntu – I accidentally removed the Trash and can longer put items into it, how can I get it back

Why don't you use another approach:

Crontab combined with command line client for trash

• Install trash-cli / sudo apt-get install trash-cli, which will allow you to control your trash folder from shell.
• Open your crontab with crontab -e in shell (will open your default shell editor chosen by select-editor)

• Add an entry like

  # In your crontab
  @reboot    empty-trash > /dev/null
  

Now on every reboot your trash will be emptied. You can specify other times to empty trash. Just look at a crontab tutorial to learn how.

Of course you can use your link approach from above just as well. The problem with your approach was that you copied the link. Most likely that broke the link. Also your newly created folder /tmp/my-trash/ didn't have the proper directory structure of a trash folder specified by the free desktop standard. That can be remedied in the following way: (FIRST empty the trash manually)

mv -r ~/.local/share/Trash/ ~/.trashcopy
cp -r ~/.trashcopy /tmp/.trashcopy
ln -s /tmp/.trashcopy ~/.local/share/Trash

To make that change persistent, you have to include the following line in your user's crontab with crontab -e or just the part without @reboot in your ~/.bashrc.

@reboot  rm -r ~/,local/share/Trash; cp -r ~/.trashcopy /tmp/.trashcopy; ln -s /tmp/.trashcopy ~/.local/share/Trash

When nautilus trashes something, it doesn't want to have to move it across partitions. This is because it takes a lot longer to move between partitions, and then if you remove the partition then the trash has no place to restore to.

Anywhere that is on the same partitions as your home directory is sent to ~/.local/share/Trash. This works across the entire root partition on setups which only have one partition.

On any other partition nautilus will make a .Trash-1000 folder on the root of the partition, then send all trashed files into that. This works rather well on external drives that you have full read/write access to, though it won't work if you don't have write permission to the root of the drive.

Because your / partition isn't the same as your /home partition, and a .Trash-1000 doesn't exist with write permission at the root of your system, nautilus will fail to trash files. Thus the delete key won't work and a trash action won't be available in the menus.

You could try using a root nautilus and deleting one file so that the /.Trash-1000 folder is created correctly, then using sudo chmod -R 777 /.Trash-1000 to give yourself permission to access a trash on the / filesystem. I cannot confirm that this will work though you could give it a try.