If you're a Linux user and into 3D printing or modeling, you might be looking for a free STL viewer to help you view and inspect your 3D model files. Luckily, there are several great options available for Linux that won't cost you a penny.

One popular choice is MeshLab, an open-source, portable, and extensible system for the processing and editing of unstructured 3D triangular meshes. It offers a range of features for visualizing and analyzing 3D models, making it a great tool for viewing STL files on Linux.

Another option is FreeCAD, a parametric 3D CAD modeler. While its main purpose is to design real-life objects of any size, FreeCAD also includes a module to prepare models for 3D printing. It can import and export STL files, making it a useful tool for viewing STL files on Linux.

If you're looking for a simple and lightweight option, consider using 3D-Tool Free Viewer. This application allows you to view and analyze 3D models and 2D drawings without any cost. It supports a wide range of file formats, including STL, making it a good choice for Linux users who need a straightforward STL viewer.

Lastly, Blender is a powerful and popular 3D creation suite that can also be used to view STL files. While it may have a steeper learning curve compared to the other options mentioned, it offers a wide range of features beyond just viewing 3D models.

In conclusion, if you're in need of a free STL viewer for Linux, consider trying out MeshLab, FreeCAD, 3D-Tool Free Viewer, or Blender. Each of these options has its own unique features and capabilities, so you can choose the one that best fits your specific needs and preferences.