rclone: rsync for Cloud Storage
One tool that speaks S3, Google Drive, Dropbox, SFTP and dozens more. Copy versus sync, the client-side encryption layer, and the command that deletes files at the other end.
Text Encodings and Locales: Why the Same Command Gives Different Answers
Linux stores text as bytes and records nothing about what they mean. What UTF-8 actually is, what the LC_ variables change, and why a script that works on your laptop…
What a TLS Certificate Actually Proves
A certificate binds a name to a key and nothing more. The chain of trust, where your machine keeps its root store, and why a site can work in a…
How a Name Is Actually Resolved on a Linux Box
Between your program and a DNS server sit nsswitch, the resolver library, and usually a local stub listener. Why dig can succeed while your application fails, and how to tell…
What a Terminal Actually Is: TTYs, PTYs and Job Control
The window is not the terminal, and the terminal is not the shell. What sits between your keystrokes and a program, why Ctrl+C stops one thing and not another, and…
sort, uniq, cut and the Rest of the Text Toolkit
The small commands that turn a log file into an answer. The count-and-rank pipeline, why uniq needs sorted input, when cut is the wrong tool, and the ones you forget…
Compression — gzip, zstd, xz and bzip2
Four tools for one job, and the choice matters. Which to use when, the flag that stops them deleting your original, using every CPU core, and how they hook into…
ip — Addresses, Links and Routes in Depth
The full ip command: the object model, the two flags that make its output readable, ip route get, and the thing nobody tells you — none of your changes survive…
journalctl — Reading the systemd Journal
Filtering by unit, priority, boot and time; following logs live; the setting that decides whether yesterday's logs still exist; and how to stop the journal eating your disk.
A Staging Environment on One Server
A second copy of your application on the same machine, with its own database and no way to email your customers. What must be separated, how to refresh it safely,…