Open source software is a contract specifying how to use and the range of terms between an Open Source SW developer and a user. Therefore, you should observe license defined by a developer to use Open Source SW; if not, license violation and copyright infringement occur, followed by punishment. This Open Source SW License basically guarantees free use, revision, and distribution by users.
Open Source SW makes and operates such license to make it compulsory to open source code within the legal limit for SW developed using Open Source SW.
As of June 2018, there are 78 licenses according to OSI that is in charge of Open Source SW licensing. However, there are a limited number of licenses being frequently used in practice.
(Korea Copyright Commission)
<Comparison of widely used open source licenses>
| license | Free use of software | Distribution of “the work” | Open the source code | Modify the source code | Redistributing of the code with changes | Proprietary software linking |
|---|---|---|---|---|---|---|
| GPL | ● | ● | ● | ● | ● | X |
| LGPL | ● | ● | ● | ● | ● | ● |
| MPL | ● | ● | ● | ● | ● | ● |
| BSD license | ● | ● | ● | ● | X | ● |
| Apache lilcense | ● | ● | ● | ● | X | ● |
