jetver is a tool written by John Tysko at Ohio University, for checking version numbers of local copies of software packages against known archives to see if the local copies are current.
In a nut shell, I wrote this to answer the question; "Do I have the most recent version of the software I am running?"
You can configure jetver to check archives using most URLs, and is able to descend ftp and gopher directory trees or cross multiple web pages and servers, all based upon the latest version number of the program you wish to download. Multiple versions on the server are easily distinguished, and the most recent release reported.
You can optionally download the file you find, or download only if it is newer than the version you currently have.
jetver is written in perl for portability. You can run it with command line options to check on a specific package, or create a data file with all of the packages you are interested in to run as a single job. In either case, you can explicitly specify your current version, or indicate a directory that contains the package on your system, and the program will determine the most recent version number in that directory. A sample file with definitions for a number of common packages is include.
The latest version of jetver is 3.0.1, and is available here. For more information, check out the README file.