Both shell- and AppleScripts can be used just about anywhere either is appropriate.

AppleScripts work better when talking to apps and user-level system facilities. (For instance, you can say tell app "iTunes" to play and it will, or tell app "Finder" to open the first file of the second window.)

Shell scripts (you referred to bash) work better when talking to low-level system objects and Unixy stuff.

They're both interoperable: you can call a shell command from AppleScript with do shell script "command here" and you can call AppleScript code from the shell with osascript -e "AppleScript". Further, there's quite a bit of overlap between the two (especially when it comes to file system operations).

There are certainly more resources for learning shell scripting online than AppleScript and it doesn't help that AppleScript has a reputation for being a "read-only" language (i.e., harder to write than read).

In any case, the most modern way to do scripting is with Automator, where you can use either shell- or AppleScripting (or both) along with pre-built modules from various apps you have installed.

As far as I know, it's not possible.

The reason is that Power Nap doesn't have an API that 3rd party apps can hook into (so apps could trigger a wake event or be notified when one occurs).

Whether this will remain like that in the future depends upon Apple. It would be interesting to see if there's a simple way to detect when one is in power nap mode, but doesn't seem to be available afaik.

If you leave a script that pulls from git every minute, in theory, since Power Nap is really a power on without graphics and audio state, maybe it would get executed (if it was running before). untested.

More info: https://stackoverflow.com/a/11692367/2684