Plan 9 from Bell Labs’s /usr/web/sources/contrib/lyndon/dbm.c
#include <u.h> #include <libc.h> // dbm to Watts void main(int argc, char **argv) { double d; if (argc != 2) { fprint(2, "usage: dbm value\n"); exits("usage"); } d = pow(10, strtod(argv[1], 0)/10.0L); d /= 1000.0L; print("%g\n", d); exits(0); }