TortoiseMerge
Version control is all about having the history of your working progress.
But to really see and check the history, you must be able to see and check
what has changed between two points in time, for example what has changed
between two releases of your product, or what was changed to fix a bug, or ...
This is where TortoiseMerge helps. It is a diff / merge software tool
for windows with a tight integration for TortoiseSVN.
Diffing files
At least for files which consist of text, TortoiseMerge can help you here.
It shows you the two versions of a file side-by-side, coloring every
modified line in that file.
You can see in that screenshot that TortoiseMerge also colors the changes
inside modified lines so you can see immediately what exactly
has changed.
When you reformat your code or text, sometimes you don't really change
anything but only split a long line into multiple ones, or you merge
multiple lines into one. TortoiseMerge marks such changes with a white
circle on the left gray bar of each view. If you see such a white
circle, you know that no real changes were made, only changes in
whitespaces.
At the bottom of the window, there is a view showing the two lines your
mouse pointer is currently hovering over. It always shows whitespace characters
with special chars, and of course it's very handy if you have long lines
because that view has the double width than the normal views.
Applying patch files
When you're working on a project and other people have access to your
source code, but not necessarily have the rights to commit changes to
the repository, you sometimes get a patch file with a bug fix or an
enhancement. TortoiseMerge helps here too, because it can apply those
patchfiles for you.
On the left is a small window containing all files which the patchfile
wants to modify. A doubleclick on those file entries opens the file
to be patched on the left, and the file how it looks like after the
patch is applied on the right side.
To approve the patch, saving the file is enough.