Linus Torvalds both companies went public and Torvalds's share value temporarily shot up to roughly US$20 million. His personal mascot is a penguin nicknamed Tux, which has been widely adopted by the Linux community as the mascot of the Linux kernel. Although Torvalds believes "open source is the only right way to do software", he also has said that he uses the "best tool for the job", even if that includes proprietary software. He was criticized for his use and alleged advocacy of the proprietary BitKeeper software for version control in the Linux kernel. Torvalds subsequently wrote a free-software replacement for BitKeeper
Operating-system-level virtualization system's resources. They include: The operating system may be able to allow or deny access to such resources based on which program requests them and the user account in the context of which it runs. The operating system may also hide those resources, so that when the computer program enumerates them, they do not appear in the enumeration results. Nevertheless, from a programming point of view, the computer program has interacted with those resources and the operating system has managed an act of interaction. With operating-system-virtualization, or containerization, it is possible to run programs within containers, to which only parts