I have published a detailed answer here: https://forums.gentoo.org/viewtopic-p-8132756.html#8132756 Here is the short version: #!/bin/bash MySerialPort="/dev/ttyUSB0" MyLatency="2" echo "#include <fcntl.h> #include <sys/ioctl.h> main() { int fd; fd = open(\"${MySerialPort}\",O_RDWR | O_NOCTTY ); int ...