Tag: sysadmin

Apt says packages have been kept back during upgrade. What the message means on Debian 12 and Ubuntu, why it happens, and how to install those packages safely.

Upgrade one package with apt and leave the rest alone. The exact flag, why apt upgrade nginx does not work, version pinning, and held package behaviour.

xargs turns stdin into arguments, build complex pipelines, run parallel jobs, and handle filenames with spaces without breaking everything.

LVM lets you resize volumes, add disks, and take snapshots without repartitioning, PVs, VGs, and LVs explained with real commands.

socat wires TCP, UDP, Unix sockets, files, and serial ports together. Port forwarding, OpenSSL tunnels, traffic capture, this is netcat with superpowers.

Create, modify, and delete users and groups on Linux, useradd, usermod, groupadd, sudo access, and /etc/passwd explained.

Monitor Linux servers with htop, iostat, netstat, vmstat, and Prometheus, pick the right tool for CPU, memory, disk, and network issues.

Your logs are in journald, not /var/log. journalctl queries that work, awk patterns that hold up, and five popular one-liners that quietly return nothing.

Set, verify, and sync your timezone in Ubuntu using timedatectl, one command to fix the clock on a newly provisioned server.

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

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

Upload an ISO to Proxmox three ways: web UI, wget onto the node, or SCP. Where ISOs live, why browser uploads stall, and how to fix storage with no ISO option.