rtapi_print_msg

It depends on the realtime version being used. If you are using RTAI then it goes into the kernel log. Otherwise it goes to stdio.

In the first case you can view it with the "dmesg" command, or by opeining a separate logging terminal and running "sudo tail -f /var/log/kernel.log"

In the latter case you can view it by starting LinuxCNC from the command line with the "linuxcnc" command.

Also, if you want to increase the logging level you can do this either in the HAL file with the "debug" command or from the terminal (after startup of LinuxCNC) with "halcmd debug 5" (or some other level from the list RTAPI_MSG_NONE = 0, RTAPI_MSG_ERR = 1, RTAPI_MSG_WARN = 2, RTAPI_MSG_INFO = 3, RTAPI_MSG_DBG = 4 RTAPI_MSG_ALL = 5)