====== Diff-mode ======

A short recipe for using the vim diff-mode to compare files for their differences.

===== Getting help =====

<code>
:h diff
</code>

===== Starting the diff-mode =====

To use the diff-mode of vim, start vim on the file to be compared:

<cli>
user@host:~$ vimdiff diff_test_1.txt diff_test_2.txt
</cli>

or

<cli>
user@host:~$ vim -d diff_test_1.txt diff_test_2.txt
</cli>

On an already running vim:

<cli>
user@host:~$ vim diff_test_1.txt
</cli>

Activate the diff-mode in the current window:

<code>
:diffthis
</code>

Split the window vertically and open the second file ''diff_test_2.txt'' in the new window:

<code>
:vnew diff_test_2.txt
</code>

Activate the diff-mode in the new window:

<code>
:diffthis
</code>

===== Leaving the diff-mode =====

Deactivate the diff-mode in the current window:

<code>
:diffoff
</code>

===== Forcing the diff-mode to update =====

Force the diff-mode to update:

<code>
:diffupdate
</code>

===== Navigating the diff-mode =====

Move forward to the next change:

<kbd>]</kbd><kbd>c</kbd>

Move backward to the previous change:

<kbd>[</kbd><kbd>c</kbd>


===== Copying changes in the diff-mode =====

Copy the differences from another buffer to the current buffer:

<code>
:diffget
</code>

Copy the differences from the current buffer to another buffer:

<code>
:diffput
</code>

===== Use diff-mode to show the changes to a buffer since the last save =====

A file is opened in vim already and unsaved changes have been made.

Activate the diff-mode in the current window containing the edited file:

<code>
:diffthis
</code>

Split the window vertically:

<code>
:vnew
</code>

Load the last saved content of the file in the new window:

<code>
:0r#
</code>

Delete the last empty line:

<code>
:$d
</code>

Activate the diff-mode in the new window:

<code>
:diffthis
</code>

All of the above steps in one single command:

<code>
:diffthis | vnew | 0r# | $d | diffthis
</code>