Download File and Verify Checksum in Bash

I had a need to download a gzip tarball file (.tgz), verify its checksum and extract one particular file in it. All in one go using Bash. By using Bash's process substitution and tee, such a task could be achieved in a one-liner. I had this need when I built a Docker image for Retype, … Continue reading Download File and Verify Checksum in Bash →

MongoDB failed to lock file on OpenShift using NFS file system

Summary This page documented the investigation of an issue: MongoDB Pod failed to lock mongod.lock on OpenShift/OKDv4. The problem was because NFSv3 was used to mount between OKDv4 Worker Nodes to the NFS server. MongoDB used internally flock/fcntl to lock the mongod.lock file descriptor. In a network file system like NFSv3, locking support was required … Continue reading MongoDB failed to lock file on OpenShift using NFS file system →

The Collector’s Fallacy – Zettelkasten Method

On researching taking notes, speciffically the Zekkelkasten method, I learned The Collector's Fallacy. In its essenses: Saving links, copying or just reading a material does not mean that you have consumed the knowledge. You may have increased the knowlege for a short time, but it will fade away very soon after that. By taking notes, … Continue reading The Collector’s Fallacy – Zettelkasten Method →

Goes back quicker in Terminal

When I was working on a Terminal, I used to type lots of cd and cd .. to go back and forth the directory. Too often, when I went to deep into the directory hierarchy, I got to type multiple times cd .. just to move up to parents, or a long command like cd … Continue reading Goes back quicker in Terminal →

Less well-known uses of curl

When it comes to make HTTP calls, I always use curl as it is a ubiquitous tool for the job. Today, I discover that I can use curl for some other tasks. copying files curl supports the FILE protocol (file:/), therefore it is possible to "download" a file: $ curl file:/path/to/some/large/file -o /the/destination/file % Total … Continue reading Less well-known uses of curl →