How many commits did we push to master in 2012?

gistfile1.md

Get the first commit of 2012

$ git log --pretty=format:'%H' --after="2011-12-31" | tail -1
d41d8cd98f00b204e9800998ecf8427e

Count the number of commits since then (inclusive)

$ git rev-list d41d8cd98f00b204e9800998ecf8427e^..HEAD | wc -l 
44555

Or put 1 and 2 together into a gorgeously cryptic one-liner!

$ git rev-list $(git log --pretty=format:'%H' --after="2011-12-31" | tail -1)^..HEAD | wc -l
44555