Pick Your Package Manager: apt, dnf, pacman
Which package manager you use depends entirely on your distro. The concepts are the same; the commands differ.
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apt: The Debian and Ubuntu Package Manager
apt is the package manager on Debian, Ubuntu, and their derivatives. These are the commands you will type every week.
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journalctl: Read Linux System Logs
Every modern Linux system logs to journald. journalctl is how you query those logs — by service, time, severity, anything.
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systemctl: Start, Stop, Enable, Status
The five systemctl commands you will type 50 times a day. Master these and you control every service on your Linux system.
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systemd and Unit Files: Write Your Own Service
systemd is the init system on every modern Linux. Writing a unit file is the standard way to make your script start on boot.
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Signals and kill: SIGTERM vs SIGKILL Explained
Signals are how Linux processes communicate. Knowing the difference between SIGTERM and SIGKILL prevents data loss.
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Background and Foreground: &, jobs, fg, nohup
How to run commands without locking your terminal, send running things to the background, and survive logout.
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ps, top, htop: See What’s Running
Three tools to inspect running processes. ps for snapshots and scripting, top for live updates, htop for visual exploration.
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sort, uniq, wc, cut: The Small Text Utilities
These four small commands plug into pipelines to count, deduplicate, slice, and order data. Learn them once and use them daily.
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sed: Stream Editor for Replacing and Transforming Text
sed edits text streams without opening an editor. The 90% use case is find and replace — but it does much more.