I do NOT want to start a fight with you, Coding Badly, but with the help of my tutorial on instructables you can program many AVR MCUs.
@alah did not ask about "many AVR MCUs". He asked a specific question about two specific tiny processors.
When @alah has his tools in place, your tutorial will make an excellent starting point.
There are other core files out there other than the ones from Coding Badly and Mark Sproul (witch are used in my instructable), so choose the ones you think are the best.
If you had taken the few seconds necessary to follow the link I posted you would have found that the opening page
of the website includes a list of cores
appropriate for tiny processors including Mark Sproul's core.
I use Mark's because they have support for many different MCUs, not only ATtinys.
His core is incomplete for tiny processors. There are much better choices available.