You can use a runtime file to give to Tochnog data on the fly (while it is running). The runtime file will be read at the start of each time step. Suppose the name of the normal input file is beam.dat, then the name of the runtime file is beam.run. The runtime file always needs to be ended with an end_data statement.
As a typical example you can use this runtime file when you are doing a long calculation and you decide while the calculation is running that you want extra output. Suppose the normal input file tn.dat contains:
control_timestep 100 ...
Then you can decide to get some extra GID plotting files, while Tochnog is already running, by using the runtime file tn.run with:
control_print_gid 100 -yes
When you want to de-activate the printing of GID files again then set the runtime file to:
control_print_gid 100 -no
As a special option, you can use exit_tochnog -yes in the runtime file; then Tochnog will exit the calculation after printing the complete database and GID files.
As another special option, you can use exit_tochnog -restart in the runtime file; then Tochnog will exit the calculation after printing the restart database and GID files (see control_print_database for an explanation on databases).