A Viewer for Day One Journal Entries in Java.
Currently it will only support Day One Journals in the default location of Dropbox/Apps/Day One. This basic functionality is more than the other viewers that I have tried on Windows. As it is written in Java, it should work on Linux. It does build on Linux, but I have not tried running it yet.
To build it you can get the source and use maven on either Windows or Linux to build.
cd dayone
mvn package
will build the executable jar file.