How to Install Linux: On a PC, a Server or a VPS
Install Linux step by step: choosing a distribution, bootable USB, partitioning, dual boot, server installs, and installing an OS on a VPS from the panel.
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Linux
Linux server administration: Debian, Ubuntu, AlmaLinux, storage, performance and troubleshooting.
setuid, setgid and Sticky Bit: Linux Special Permissions
What the setuid, setgid and sticky bits do, how to set them with chmod, reading s, S, t and T in ls output, shared directories, and auditing setuid files.
umask Explained: Default File Permissions in Linux
How umask sets default permissions for new files and directories: the calculation, 022 vs 002 vs 077, per user, per systemd service and in scripts.
Format a Disk on Linux with mkfs (ext4, XFS, Btrfs)
Create filesystems with mkfs: ext4 vs XFS vs Btrfs, labels, reserved blocks, inode counts for many small files, checking with fsck, and safe formatting steps.
How to Kill a Process in Linux: kill, pkill and killall
Stop processes on Linux the right way: SIGTERM vs SIGKILL, kill by PID, pkill and killall by name, freeing a port, stubborn D-state processes and services.
Grow a Linux Partition After a Disk Upgrade (growpart, resize2fs)
Use the extra space after a VPS disk upgrade: grow the partition with growpart, then the filesystem with resize2fs or xfs_growfs, online and without a reboot.
ZFS on Linux: Install, Create Pools, Datasets and Snapshots
Set up OpenZFS on Ubuntu or Debian: mirror and RAIDZ pools, datasets with compression, ZFS snapshots, send/receive backups, scrubs and ARC tuning.
tcpdump Command: Capture and Analyze Network Traffic on Linux
Capture packets with tcpdump: filter by host, port and protocol, read the TCP handshake, debug connections and DNS, and save pcap files for Wireshark.
chown Command in Linux: Change File Owner and Group
Use chown to change the owner and group of files and directories: syntax, recursive changes, symlinks, numeric IDs, chgrp, and fixing web server ownership.
Partition a Disk with fdisk on Linux (Step by Step)
Partition a new disk with fdisk: GPT vs MBR, create and delete partitions, set types, write changes, inform the kernel, and format and mount the result.
parted Command: Partition Large Disks with GPT on Linux
Use GNU parted for disks over 2 TB: create GPT labels, make aligned partitions, resize partitions, script parted non-interactively, and compare with fdisk.
sar and sysstat: Historical CPU, Memory, Disk and Network Stats
Enable sysstat to record performance history, then use sar to see CPU, memory, swap, disk and network usage for past hours and days.
Fix Common apt update Errors on Ubuntu and Debian
Fix apt update and upgrade errors: NO_PUBKEY, no Release file, dpkg lock held, unmet dependencies, hash sum mismatch and end-of-life releases.
Duplicati: Encrypted Backups With a Web UI (Docker Setup)
Set up Duplicati with Docker: web UI over SSH, backup jobs to S3, B2 or SFTP, AES encryption, schedules and retention, restores, and restic as an option.
eBPF Basics for Server Admins: bpftrace and BCC Tools
eBPF for server admins: safe in-kernel tracing, ready-made BCC tools like execsnoop, opensnoop and biolatency, bpftrace one-liners, and requirements.
sh vs bash vs zsh vs fish vs dash: Linux Shells Compared
sh, dash, bash, zsh and fish compared for interactive use and scripting: portability, shebangs, bash-only features, changing the default shell, server tips.
sed Command in Linux: Find, Replace and Edit Text with Examples
Learn sed with practical examples: substitute text, edit files in place safely, delete and print lines, work with ranges, regex groups and config file edits.
cut Command in Linux: Extract Columns and Fields (Examples)
Extract fields from CSV, /etc/passwd and logs with cut: delimiters, field ranges, characters and bytes, complement, and when awk is the better tool.
systemd Timers: A Modern Alternative to Cron (with Examples)
Schedule jobs with systemd timers: .service and .timer units, OnCalendar syntax, persistent and randomized timers, journald logs, and timers vs cron.
iostat Command: Measure Disk I/O, Utilization and Latency
Read iostat -x output: IOPS, throughput, await latency, queue size and %util, find the process doing I/O with iotop, and spot disk bottlenecks.
logrotate on Linux: Rotate, Compress and Clean Up Log Files
Configure logrotate for app and Nginx logs: daily or size rotation, compression, retention, copytruncate vs postrotate, testing with -d, and fixes.
mosh: A Mobile Shell That Survives Network Changes
Use mosh instead of SSH on unstable or mobile connections: install it, open UDP ports, how roaming and local echo work, and limits like scrollback.
Debian sources.list Explained: Repositories, Components, Mirrors
Debian APT sources explained: sources.list and deb822 files, main, contrib and non-free, security and updates suites, mirrors, and safe third-party repos.
Clone a Linux Server to a New VPS (rsync, Ansible or Images)
Copy a Linux server to a new VPS: rebuild-and-restore vs full rsync clone, what to exclude, fixing hostname, SSH host keys and machine-id, and testing.