TOPIC / TAG
Notes in linux
13 articles
Add a Swap File to a Small VPS
Check memory first, create a swap file that survives reboots, set vm.swappiness with a sysctl drop-in, and remove it cleanly if you change your mind.
A Safe 90-Second Linux Disk Space Triage
A read-only sequence for finding what filled a Linux server before deleting logs, images, caches, or data you may still need.
systemctl cat and Drop-In Overrides
Inspect the complete systemd unit and make a small local override without editing vendor files.
systemd Timers Without the Guesswork
Create a small systemd timer, inspect its next run, and make missed jobs predictable after downtime.
A Calm SSH Host Key Check
Check what really changed when SSH warns about a new host key, before deleting the old entry from knownhosts.
Reading a Failed systemd Service Without Scrolling Forever
A compact sequence for checking a failed systemd unit, its recent logs, and the exact configuration systemd loaded.
SSH Config Aliases for a Small Fleet
Replace long SSH commands with readable host aliases while keeping usernames, ports, keys, and jump hosts explicit.
Disabling IPv6 on a Linux Server, and When Not To
Decide whether disabling IPv6 actually solves your problem, then do it with a sysctl drop-in or the ipv6.disable=1 kernel parameter on Debian, Ubuntu, Rocky Linux, or AlmaLinux, verify the result, and roll it back.
The First Hour on a Fresh Debian or Ubuntu VPS
Set up a sudo user, SSH keys, an sshd drop-in that blocks password and root logins, a ufw firewall, and automatic security updates on a new Debian or Ubuntu server, checking each step as you go.
A Gentle First Pass With journalctl
Start with a narrow journalctl query and widen it deliberately instead of scrolling through the entire system journal.