Passing variables to shell commands

Shell commands in the notebook are executed in a temporary subshell.

Communication in the other direction–passing Python variables into the shell–is possible using the {varname} syntax:

message = "hello from Python"

and use in another cell:

!echo {message}

The cell output will be:

hello from Python

The curly braces contain the variable name, which is replaced by the variable’s contents in the shell command.

For more tips like this one: see the %magic IPython commands and the section with a quick overview in this publication.