Mine
public text v1 · immutable# dtrace -p 102921 -n 'pid$target:libc:read:entry { printf("fildes:%d\n",args[0]); }'
dtrace: invalid probe specifier pid$target:libc:read:entry { printf("fildes:%d\n",args[0]); }: in action list: index 0 is out of range for pid102921:libc.so.1:read:entry args[ ]