Suppose that I have a script executable on a Linux remote server shared by other employees. (it could be a bash .sh script, a julia .jl script, for example). I believe tasks of all users are affected FIFO. How can I assure that there is exactly a fixed number (for instance 4 or 1) of core(s) totally available for my numerical experiments?

Suppose that I have a script executable on a Linux remote server shared by other employees. (it could be a bash .sh script, a julia .jl script, for example). I believe tasks of all users are affected FIFO. How can I assure that there is exactly a fixed number (for instance 4) of cores totally available for my numerical experiments?