When it comes to using someone else's work without permission, the answer is not always straightforward. It depends on the type of software license that is in place. For instance, the GNU General Public License (GPL) and Mozilla's Public License 2.0 are two popular copyrighted free software licenses. The GPL allows users to combine covered software with one or more secondary licenses, as long as the covered software is not incompatible with the secondary licenses.
On the other hand, Mozilla's Public License 2.0 usually has a one-year term and must be purchased along with the software. Alternatively, software owners can choose to make the source code available to users and allow them to freely use, copy, modify and redistribute the software under open source licenses. This means that if the end user of the software is the owner of the corresponding copy, then they can legally use the software without a license from the software publisher. When it comes to understanding open source software licenses, it is important to note that there are two main categories: permissive licenses and restrictive licenses. Permissive licenses are generally easier to comprehend and are a good starting point for those who are new to open source software. Restrictive licenses, also known as copyright or reciprocal licenses, require that any derivative work must be licensed under the same open source license as the original software. It is also essential to note that neither the SSPL nor the Elastic license have been approved by the Open Source Initiative (OSI).
This means that these licenses may not be suitable for all projects. Finally, for open source software with a permissive license, all that is usually required is a notice. In conclusion, when it comes to using someone else's work without permission, it is important to understand what type of license is in place. If you are using open source software with a permissive license, then you may be able to use it without a license from the software publisher. However, if you are using restrictive or copyright licenses, then you will need to obtain permission from the copyright holder before using their work.