The flagfile can be used to interrupt a potfit run softly. Every few steps the presence of the flagfile is checked and if it is found, the current optimization algorithm is aborted. This means that if the simulated annealing algorithm is running and a flagfile is created, simulated annealing will be terminated and potfit will continue with the powell minimization.

The content of the flagfile is not read, only the existence is checked. An empty file can be created quickly with the touch command:

touch flagfile

If the flagfile has been detected and the optimization has been terminated, it will be deleted.