Enforcement of programing tools licenses
<p>Some time ago I became a university student and with that I got an access to serveral programming tools, such as Jetbrains' products, for free. The licences I got are of course only for academic purposes, which got me wondering: How do they enforce these types of licenses? When you load a .cpp/.h/etc files in for example notepad you can't tell in which program they were typed before, so how do they know if that commercial code was written in a program with non-suited license for a such usage?</p>

<p>Another thing I thought about is: How do you "free" your code from the license of the program you wrote it in? For example, if I copy the contents of my file written in editor XYZ (with license only for academic purposes) to an open source editor, can I still not distribute it? What if I wrote my source code in XYZ program, but futher changes occured in the open source program? Is that "old" part of the code is still under that program license?</p>

<p>If you create something with someone else's software, what you've created is yours.  The only exception would be if the software tool in question embedded a significant amount of its own code or data into the produced file, and that isn't going to happen with a text editor.  (One case where it would happen is a parser generator, which is a program to produce a computer language parser.  The parser generator would normally provide the parsing code, which would remain copyrighted by whoever had the copyright to the parser generator, and a large data table.)</p>

<p>As you point out, it would probably be impossible to establish that a file was created using a JetBrains software tool.  Students are notoriously unprofitable to sue, anyway, so I really doubt JetBrains would pay any attention.  In addition, the purpose of student licenses is usually to get students used to working with their software, so they'll want it when they get jobs out of school, so JetBrains wouldn't want to seem unfriendly.</p>

<p>It's also not clear what they could do to you if you used a student version of their software for commercial purposes.  They'd need some basis to sue you for damages, and it would be hard to prove any beyond the retail cost of the software.</p>

<p>So, you're in the clear.  If your commercial venture makes enough money to be worthwhile, you'll be able to afford retail versions of the JetBrains products.</p>

licensing