This is a very simple app to sync files from local directory to Amazon S3. The reason I choose Java is because it can be run anywhere with a single JAR file.
To compile, compile with Amazon SDK for Java.
First, create a file called "s3credentials.properties" somewhere and put in:
Then, to use it, do something like:
java -jar tos3.jar <directory> <bucket> <path-to-s3credentials.properties> preview
It will show which files to add, or to remove.
Finally, remove the last word, "preview" to make it sync!