The command-line utility CFDProcessor has a limited interactive or batch command mode. The command mode can be entered during the solver execution by issuing the SIGINT signal (corresponds to the keyboard shortcut Ctrl + C in common terminal emulators). If this is done, CFD Processor will check if the directory with the running calculation contains a file named cfdp-command.txt; if the file is found, commands are read from it (= “batch command mode”). If the file is not found, CFD Processor will prompt the user for interactive entry of commands (= “interactive command mode”). The currently known commands are the following:

• help — Display list of available commands.
• abort — Terminate calculation at the end of the next iteration.
• abortwrite — Terminate calculation at the end of the next iteration, write the last calculated solution to the corresponding time directory.
• suspend — Pause the calculation (in memory).
• continue — Resume the paused calculation.
• next — Skip to the next calculation point.
• kill — Forcibly terminate CFDProcessor.

The command mode can be used to terminate a detached calculation with a checkpoint being written. Provided that “DIR” is the directory with the calculation and “PID” is the process ID of the running CFDProcessor program, the following two commands will do the trick:

# echo abortwrite > DIR/cfdp-command.txt

# kill -SIGINT PID