Now that my sensors are successfully collecting data and the data is being processed by a Node-RED flow on my Raspberry Pi the final step is to add some persistence to the data. As it stands the data is constantly streaming and being displayed on a dashboard but after that it’s discarded so there’s no …
Category archives: Linux
Format and Mount External Hard Drives in Linux
Assuming you’ve just bought a new external hard drive or you have one that’s already in use these are the steps you need to take to make it usable with Linux. ⚠️ Be aware that following these steps will reformat the drive causing all data to be permanently erased. You’ve been warned. First connect the …
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Recovering Node-RED Flows After Changing Hostname
I recently changed the hostname on my Raspberry Pi and was rather surprised (and initially worried) when the next time I started Node-RED all my flows has disappeared 😱 It turns out that the flows are connected to the computer hostname by their naming convention. Someone even filed a bug regarding this unexpected behavior. The …
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Piping Bitcoin RPC Commands
If you want to get the block header of the latest block generated on the bitcoin blockchain using bitcoin-cli it’s a little tricky (and hard to say!). You need to first find the latest block number (height), then find the hash of that block and then get the header using the hash. Since the getblockheader …
Linux Command Line Calendar
I’ve used Linux for almost 20 years and somehow never knew you could get a calendar on the command line 🤯🤯 Just type ‘cal’ for the current month or cal followed by the year (‘cal 2019’ for example) to get a full year. See the man pages for details. me@myserver:~$ cal 2019 2019 January February …
Running a Bitcoin Full Node on a Raspberry Pi 4
First Attempt I’ve wanted to run a Bitcoin full node for a while now. Not because it makes any money, quite to the contrary, it actually costs money to run a node, but to better understand a technology there’s nothing better than learning by doing 🧠 A full node is a program that fully validates …
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Uploading Files Over SSH Using KNIME
If you have SSH access to a server and want an easy, visual way of uploading files that can be automated and scheduled then using KNIME works great. Fortunately KNIME already has an SSH Connection node so the set up is very easy. The basic flow is as follows: Make a connection the ssh server …
WordPress File Size Limits on Nginx
So my WordPress is up an running and inevitably I hit a few roadblocks on the way. While trying to upload a video I encounter the classic ‘HTTP error’ that seems to be almost always due to file size limits on the server. In my case the fix was simple but requires changing both setting …