I found myself in need of the latest version of WPILib, and didn't want to go through the process of installing the update. So, I came up with a workaround. Here's some shell code that will get the latest version of WPILib. I present it here in the hopes that you will find it useful.
Code:
#!/bin/bash
wget -q http://firstforge.wpi.edu/sf/frs/do/viewSummary/projects.wpilib/frs -O - | grep 'WPILib C++ update' | sed "s/.*<a href=\"\([^\"]*\)\">.*/http:\/\/firstforge.wpi.edu\1/" | uniq | sed "s/;.*//" > wpilib_page1.url
wget `cat wpilib_page1.url` -q -O - | grep "rel[0-9][0-9]*" | grep href | sed "s/.*\(rel[0-9]*\)/\1/" | sort -r | head -n 1 | sed "s/.*<a href=\"\([^\"]*\).*/http:\/\/firstforge.wpi.edu\1/" | sed "s/;.*//" > wpilib_page2.url
wget `cat wpilib_page2.url` -q -O - | grep "\.exe\s*<\/a>" | sed "s/.*<a href=\"\([^\"]*\)\".*/http:\/\/firstforge.wpi.edu\1/" | sed "s/;.*//" > wpilib_page3.url
wget `cat wpilib_page3.url` -q -O wpilibupdate.exe
mkdir wpilibinstaller
cd wpilibinstaller
unzip ../wpilibupdate.exe | tee unziplog.txt
cat unziplog.txt | grep "inflating: WPILib/.*\.zip" | sed "s/.*\(WPILib\/.*\.zip\).*/\1/" | xargs -I '{}' cp '{}' ../
cat unziplog.txt | grep "inflating: WPILib/.*\.zip" | sed "s/.*WPILib\/\(.*\.zip\).*/\1/" | xargs -I '{}' ln -s '{}' ../WPILib.zip
cd ../
rm -r wpilibinstaller
rm -f wpilib_page1.url wpilib_page2.url wpilib_page3.url