This Vim Tip demonstrates how to use the Vimdiff functionality to compare and edit two files simultaneously.

First, the `vim -d jail1 jail2` command opens two files named jail1 and jail2 in Vimdiff mode, which displays the files side by side, highlighting the differences between them.

Next, the command `3]c` jumps to the third difference in the files and enters the "change" mode, allowing any text within the difference to be edited.

After making the desired changes, hitting `Esc` returns to command mode, and `]c` jumps to the next difference for editing, and `dp` switches the text within the difference under the cursor with the text in the subsequent difference.

Finally, `:wqall` saves the changes made to both files before exiting Vimdiff mode.