Use environment variables in External Tool (Labs)


I want to use environment variables in External Tool (Labs).  However, whenever I try to use one for something as simple as:

/bin/bash -c "echo $HOME"

I get an error for "Invalid variable placeholder". 

What's happening, of course, is that $HOME is being interpreted as a KNIME flow variable.  But I want it interpreted as an environment variable in the shell.  Is there any way to get the interpretation I want?


You can use Extract System Properties node to read and later create flow variables. (Extract Context Properties contain the KNIME specific properties.) After that, you can use it like this (not tried, just guessing it works similarly to other nodes): /bin/bash -c "echo $${SHOME}$$"

A larger problem might be, when the external tool to execute requires the presence certain environment variables, though it seems that is not possible to set. Maybe in a newer version?

Cheers, gabor