$ make flash
avrdude -c stk500v2 -P /dev/tty.usbserial -p attiny84 -U flash:w:main.hex:i

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.01s

avrdude: Device signature = 0x1e930c
avrdude: NOTE: FLASH memory has been specified, an erase cycle will be performed
         To disable this feature, specify the -D option.
avrdude: erasing chip
avrdude: reading input file "main.hex"
avrdude: writing flash (126 bytes):

Writing | ################################################## | 100% 0.10s

avrdude: 126 bytes of flash written
avrdude: verifying flash memory against main.hex:
avrdude: load data flash data from input file main.hex:
avrdude: input file main.hex contains 126 bytes
avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 0.08s

avrdude: verifying ...
avrdude: 126 bytes of flash verified

avrdude: safemode: Fuses OK

avrdude done.  Thank you.