On Mac (and Linux I think), after you have created your AVD, you can make an alias:
alias run-android='~/Library/Android/sdk/tools/emulator -avd ${YOUR_AVD_NAME} &'
Note: the execution of the alias will not lock your terminal, if you want that, just remove the last '&'.
Run emulator
it self will give you an error because he expect that, in your current position, you have: /emulator/qemu/${YOUR_PATFORM}/qemu-system-x86_64'
to start the emulator.