Command line options can be used to override setting in the configuration file. The command line options KKFChess knows are:
| Option | Arguments | Description |
| -? | Displays the acceptable command line options. | |
| -b | <file> | Sets the opening book file. |
| -c | <file> | Initialise engine with another configuration file. |
| -d | <depth> | Sets the maximum search depth. |
| -e | <paths> | Sets the Nalimov EGTB paths. |
| -f | <fen> | Starts the engine in the given position. |
| -g | Disables EGTB lookup. | |
| -h | <size> ["KB" | "MB"] | Sets the positional hash table sized. |
| -k | Disables opening book lookup. | |
| -l | Enables logging. | |
| -n | <size> ["KB" | "MB"] | Sets the pawn hash table size. |
| -t | <secs> | Sets the maximum think time. |
| -v | Shows program version and compile-time options. |
You can create multiple configuration files and use them as "personalities" with the "-c" option. Multiple options are recognised.