Bash node flow Variable

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1

Hi all,

I'm trying to recall a flow variable in a bash command of the bash node.

Which is the correct way to do it?

I've a flow variable dir that has a value /home/myname.

Let's say I want to list it and put the output to a file:

ls $dir > file.txt

don't work. The var is not recognized. I'm testing the way by echo command, but I still cannot find the right way. What's the right syntax accepted by this node/knime?

Thanks and sorry if this is a too much basic question

Thanks

Andrea

 

 

2

Hi Andrea,

Thank you for your question. One way of doing that is like this: use the String manipulation (Variable) node where you can create the complete bash command including the flowvariable (something like join(“ls”, $${dir}$$, “> file.txt”)). Subsequently you can use that command as variable for the Bash command (in the flow variables option B_cmd). Does that help?

Let me know if you have further questions,
Jeany

1 Like
3

Hi Jeany, thanks for the reply.
I’ve been working that way and it goes…however I was thinking in something “direct” in the bash node…It would be certainly faster than creating the commands “outside”. There’s no way of reading/use the flow variables inside the bash node?
Thanks again
Andrea

4

Yes, that would certainly be nice to have, unfortunately this is not possible at the moment in the bash node. The nodes External tool (labs) and External tool offer a little more flexibility on the parameters. You might take a look at them in case creating the command with the String manipulation node costs too much time.
Best,
Jeany