I am wanting to fix a message I am getting. This is the message: {"_msgid":"3c5b556c.b18d0a","topic":"","payload":" Used\n 688\n","rc":{"code":0}} What I want to get is the amount of usage on a USB stick and map it to a gauge. I found the command: df --output=used /dev/sda1 (If that can be mad…

You could probably do it with JSONata (but I have no clue how). I would first look up the df command help see if any command line parameter might simplify the output. If not, then I'd use a regular expression. Something like (\d+). Here is a working example Ps, that site also generates the is cod…

Thanks Steve. I worked out if I string and delLeftmost to a \n I get 688. But then I put it through a function node and convert it to an int value. var x = parseInt(msg.payload); msg.payload = x; return msg; Then send it to the gauge node. Looks good. But appreciated.

You don't even need to create the x variable msg.payload = parseInt(msg.payload) will do the trick nicely

Yeah, I think that is a layover from other problems parsing variables where sometimes it can't deal with something like msg.payload. Or have I got that bit wrong too? (Sorry. Brain drain happening.)

[image] Steve-Mcl: You could probably do it with JSONata (but I have no clue how). Or in JSONata in a change node after the command output, set as Payload to JSONata expression. $number($match(payload, /(\d+)/)[0]['groups'][0]) (Typing from phone, pretty sure it’s typo free but untested) W…

Yet another way - grep the result from the original command via a pipe df --output=used / | grep -v Used then just feed into the gauge (as it will cope with simple text.) [{"id":"425a6c38.bcad84","type":"inject","z":"df0a9f4b.bc75b","name":"","topic":"","payload":"","payloadType":"str","repeat":"…

Sooo, many ways! Aren't computers fun :smiley_cat:

(How embarrassing.) I already had most of that flow already. I just hadn't added the GUI. One way I did it was: df -h /dev/sda1 | grep / | tr -s ' ' | cut -d " " -f4 But that shows me the remaining spavce - I think. I didn't know the --output=used bit then. And the way I did it last night wa…

I remember a very, very old ad from the late 70's...it was a cartoon and it was an ad for,,,yes,,,IBM Two men standing looking at a construction site - if it wasn't for that excavator, 100 more men with shovels would have a decent job - yeah, and if it wasn't for those shovels, it could be 1000 m…

Just a tip; there's a set of very handy system nodes , which includes a disk-space node, as well as CPU usage, free RAM, and system uptime. They use the Node.js OS library and are compatible with both Linux and Windows. I've been using these on a Pi for the last couple of years with zero issues. [Sc…

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Help with shell command to get a result in a node

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Trying_to_learn 16 September 2019 20:48 12

Looks nice.

Thanks.

Shall install and use.

1 Like

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Help with shell command to get a result in a node

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