What you posted does work. I was just saying that if you don't want to deal with having to type those three commands in quick succession, one of the above solutions was necessary.

If I understand correctly, handshakes only happen when clients try to communicate with the access point. So if you're the only one there, and no one else is connecting to your test wifi point, you're not going to get handshakes.

Good monitor mode tests would be aireplay-ng -9 wlan0, or, say, airodump-ng (but without any options, so that it just shows you a terminal with a bunch of outputs). If you can detect traffic, and injection reports itself working (and actually seems to work), monitor mode is fine, and it's just something about catching handshakes that's wrong.

For testing purposes, you can also set up a WEP access point instead of WPA, and then see if you can capture IVs.