Hi guys, I'm brand new to Node Red and learning linux command line on the fly. I have come up with a command that returns my CPU Temp. I'm trying to implement this for an ARM64 CPU piece of hardware. After having weird results in Node Red I decided to test this same code on my laptop running Ubuntu…

I believe your issue with the exec node is caused by the use of input redirection and/or trying to use Command Substitution. Digging deeper now.

Thank you, appreciate the help. Open to suggestions.

The first issue you should tackle when using node-red's exec node is to break up any piped and/or chain commands. As the last command executed will give you your Standard output and Standard error. I'm going to walk you through how my brain tries to find a bug. I'm sure your higher up in skill than…

HOLD UP!!!!!!! old-style backquote method of command substitution works. Go figure. When the old-style backquote form of substitution is used, backslash retains its literal meaning So I use: cputemp=`cat /sys/class/thermal/thermal_zone0/temp` && echo "$((cputemp/1000)) c" in node-red exec node …

I haven't tried it but perhaps it would be better to use a file in node to read it rather than cat.

You are Correct! the file method works just fine...... Better to use a all node-red implementation than using exec node for this one. [example2] import this flow: [{"id":"e80a2f5b.7a9de8","type":"tab","label":"File Method Temp C","disabled":false,"info":""},{"id":"510da242.80f2dc","type":"file …

I was too slow to edit NR on my tablet but here's another example using JSONata expression in a change node. No need for function nodes. [{"id":"6da8bc3b.faa0a4","type":"inject","z":"bf210454.b85538","name":"","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":false,"onceD…

@ristomatti So many ways to skin this cat......loving it :heart_eyes:

The original command from @MrRum likely did not work as it uses shell features. If insisted, it should work if it was a separate script to exec. Let's say read_temp.sh: #!/bin/bash cputemp=$(</sys/class/thermal/thermal_zone0/temp) && echo "$((cputemp/1000)) c" # or alternate easier to read versio…

Thanks @meeki007 , @ristomatti , Colin for the help. As you can probably tell I don’t have a CS background but I’ve been on the hardware side for many years and I’ve hacked other things together in the past but not using Node Red or Linux. Since the primary function of the device is to collect data …

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Exec Node not giving same output as linux terminal

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thebaldgeek 31 May 2020 00:37 16

For my system dashboard network stats, I use this node; https://flows.nodered.org/node/node-red-contrib-linux-network-stats

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Exec Node not giving same output as linux terminal

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