Claim: Linux is software that does not cost money and is available for unrestricted modification.
Evidence: oggˈlɪnəks -RSB- or , less frequently , -LSB- ˈlaɪnəks -RSB- -RRB- is a Unix-like computer operating system assembled under the model of free and open-source software development and distribution.
That is , anyone is freely licensed to use , copy , study , and change the software in any way , and the source code is openly shared so that people are encouraged to voluntarily improve the design of the software.