PackStudio is an application for making Minecraft Resource Packs.
PackStudio works on any platform, but the GUI will require JavaFX. JavaFX is included with Java 8, but will need to be installed for newer versions of Java.
To run PackStudio, simply double click the JAR, or type:
java -jar PackStudio.jar
PackStudio will create a .packstudio directory in your home directory, which wil contain your settings.