$ ps uaxw |grep python |grep -v grep

abarnert         1028   0.0  0.3  2529488  55252 s000  S+    9:46PM   0:02.80 /Library/Frameworks/Python.framework/Versions/3.4/Resources/Python.app/Contents/MacOS/Python /Library/Frameworks/Python.framework/Versions/3.4/bin/ipython3

abarnert         9639   0.0  0.1  2512928  19228 s002  T     3:06PM   0:00.40 /System/Library/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python /usr/local/bin/ipython2

$

$ ps uaxw |grep python |grep -c -v grep

2