protect command line linux program

Question

I have to deliver a command line Linux executable to a company as a trial. If they like it, they are supposed to buy it afterwards. My worry is that the program is unprotected and they could keep it after the symbolic trial period, redistribute it or copy it.

Is there any easy way to provide basic protection to the executable? For example not being able to execute it after a given period...

Thanks!!!

Answer 1

Check the current timestamp on startup, and immediately exit if the trial period has elapsed. Of course, they could change the system date, but that's probably not worthwhile unless your program is very valuable to them.

If you want to go further, you could make a call to a server that you control, to determine whether the program should keep running. Or, for that matter, to a well-known NTP server.

Of course, they could still bypass that protection by running in a debugger and simply skipping the test. If they have that level of skill then there's nothing that you can do (but it's also unlikely that they'd need your programming skills in the first place).