Update or commit: See what's changed in a version-controlled file with svn diff

When you run
sudo svn status -u
and see

M 6549 www/.htaccess

you can see exactly what's up with those changes with
svn diff www/.htaccess
Showing something like:
Index: www/.htaccess

===================================================================
--- www/.htaccess (revision 6549)
+++ www/.htaccess (working copy)
@@ -86,7 +86,7 @@
# VirtualDocumentRoot and the rewrite rules are not working properly.
# For example if your site is at http://example.com/drupal uncomment and
# modify the following line:
- # RewriteBase /drupal
+ RewriteBase /
#

By the identification of the plus line with the change and the working copy, we can see that this is a change we should be pushing out to the test servers, since it was apparently made directly on live (where we are now). This can be accomplished with:
agaric@exampleserver:/sites/example$ sudo svn commit -m "commit change made on live to repository" www/.htaccess

Sending www/.htaccess
Transmitting file data .
Committed revision 6696.

Resolution