Tag: sysadmin

Count files in a directory (recursively or not) with find, ls, and tree, quick one-liners for when du just isn't telling you enough.

Your disk is full and du is lying to you. ncdu, df, and find tricks to track down space hogs before your server goes down at 2 AM.

Use su with a specific shell to switch users without the default login shell, useful when /etc/passwd points to something unexpected.

logrotate keeps your /var/log from eating the disk, configure rotation schedules, compression, and retention for any service log.

Master MySQL from the command line: connect, query databases, manage users, repair tables, optimize, everything you keep Googling, one reference.

Upload an ISO to Proxmox three ways: the web UI, wget straight onto the node, or SCP. Which to use when the browser upload stalls, plus checksum verification.

Clean up empty directories with find and rmdir, safely prune orphaned dirs left after file migrations.

Old kernels pile up in /boot and eat disk space, safely remove unused kernels on Ubuntu and Debian with apt and dpkg.

Remove spaces and special characters from filenames using bash loops, rename, find, and parameter expansion tricks.

Service restart not showing logs? systemd hides stdout. Learn journalctl, systemctl status, and debugging workflows for silent systemd failures.

You get 50 alerts a day and ignore all of them. That's not monitoring, that's noise. Here's how to build alerts people actually care about.

MySQL 8.0 broke auth, MariaDB forked hard, and Docker changed how you connect. Here's what still works and what'll bite you.