Can I access python variables within a `%%bash` or `%%script` ipython notebook cell?

Is there a way to access variables in the current python kernel from within a %%bash or other %%script cell?

Perhaps as command line arguments or environment variable(s)?

Python variables can be accessed in the first line of a %%bash or %%script cell, and so can be passed as command line parameters to the script. For example, with bash you can do this:

%%bash -s "$myPythonVar" "$myOtherVar"
echo "This bash script knows about $1 and $2"

The -s command line option allows you to pass positional parameters to bash, accessed through $n for the n-th positional parameter. Note that what's actually assigned to the bash positional variable is the result of str(myPythonVariable). If you're passing strings containing quote characters (or other bash-sensitive characters), you'll need to escape them with a backslash (eg: \").

The quotes are important - without them the python variables (string representations) are split on spaces, so if myPythonVar was a datetime.datetime with str(myPythonVar) as "2013-10-30 05:04:09.797507", the above bash script would receive 3 positional variables, the first two with values 2013-10-30 and 05:04:09.797507. It's output would be:

This bash script knows about 2013-10-30 and 05:04:09.797507

If you want to name the variables and you're running linux, here's an approach:

%%script env my_bash_variable="$myPythonVariable" bash
echo myPythonVariable\'s value is $my_bash_variable

You can specify multiple variable assignments. Again beware of quotes and other such things (here bash will complain bitterly!). To grok why this works, see the env man page.

To include python variables within bash commands run using the syntax !<some command> you can use {<variable>} as follows:

In [1]: for i in range(3):
   ...:     !echo {i+1}
   ...:     
1
2
3

While this is slightly different from what the OP asked, it is closely related and useful in performing a scripting task. This post has more great tips and examples of using shell command within IPython and Jupyter notebooks.