PyMOL is a cross-platform, free and open-source, molecular visualization software written in C, C++ and Python and developed by Schrödinger, LLC.
Use this tag for questions relating to PyMOL, its installation (in which case the software-installation tag may also be appropriate), customization and usage. Additional support resources may be found below in the Support section of this tag wiki.
Installation
PyMOL may be installed on Ubuntu by running sudo apt-get install pymol, keeping in mind that this version is often out of date (e.g., as of 16 May 2015 the latest version of PyMOL available on 15.04 is 1.7.2.1 and the latest version is 1.7.6). Alternatively the latest version of PyMOL may be compiled and installed from source code (instructions may usually be found in the INSTALL file within the source code directory, or here). If any issues are encountered in this process, feel free to ask a question here regarding its installation.
Usage
PyMOL may be used for a variety of different purposes, including making movies or images depicting the 3D structure of macromolecules or small molecules. It can also be used to calculate the electrostatic interactions between a macromolecule and its ligand(s) using the APBS plugin.