Linux Directory Structure Explained (/etc, /var, /usr, /opt…)
The Linux filesystem hierarchy for server admins: what lives in /etc, /var, /usr, /opt, /home, /tmp and /proc, where configs, logs and data go, and backups.
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Linux
Linux server administration: Debian, Ubuntu, AlmaLinux, storage, performance and troubleshooting.
etckeeper: Track /etc Changes in Git on Linux Servers
Version-control server configuration with etckeeper: install, automatic commits on package changes, history and diffs, rolling back a file, and safe remotes.
Disaster Recovery Plan for a Linux VPS: Step-by-Step Template
Build a disaster recovery plan for Linux servers: RTO and RPO, what to back up, documented rebuilds, runbooks for common disasters, restore drills, upkeep.
The /proc Filesystem: Read System and Process Info on Linux
Explore /proc for troubleshooting: CPU and memory info, load, per-process status, command lines, environment, open files and limits, and /proc/sys.
Vim Basics: Edit Files on a Linux Server Without Panic
The Vim survival guide for server admins: modes, opening, editing, saving and quitting, search and replace, copy and paste, undo, and a minimal useful vimrc.
passwd Command in Linux: Change Passwords and Lock Accounts
Change your own or another user’s password with passwd, force a change at next login, lock accounts, set ageing with chage, enforce strong passwords.
Linux Hidden Files (Dotfiles): Show, Create and Manage Them
How hidden files work on Linux: the dot prefix, ls -a, key dotfiles like .bashrc, .ssh and .env, copying and finding them, and keeping them out of web roots.
How to Check Your Linux Version, Distribution and Kernel
Find which Linux distribution, release, kernel and architecture a server runs with os-release, hostnamectl and uname, plus end-of-life checks.
Environment Variables in Linux: Set, Export and Persist Them
Set, export and persist Linux environment variables per user or system-wide, and pass them to systemd services, cron jobs and sudo.
netcat (nc) Command: Test Ports, Transfer Files, Debug Services
Use netcat to test whether a TCP or UDP port is reachable, listen on a port, send raw HTTP or SMTP, transfer files between servers and check firewalls.
High I/O Wait on Linux: Find What Is Slowing Your Disk
Diagnose high iowait: confirm it with top and vmstat, find the disk with iostat and the process with iotop, then fix swapping, slow queries and backups.
nice and renice: Set Process Priority on Linux
Control CPU priority with nice and renice, disk priority with ionice, set priorities for services and cron jobs, and keep backups from slowing your site.
zram Swap on Linux: Compressed RAM Swap for Small Servers
Set up zram compressed swap with zram-tools or zram-generator, choose size and algorithm, combine it with disk swap, and check compression stats.
diff Command in Linux: Compare Files and Directories
Compare files with diff: reading unified output, side-by-side view, ignoring whitespace, comparing directories and remote files, creating patches.
Bash Scripting Tutorial: Write Reliable Scripts for Servers
Learn bash scripting for servers: shebang, variables, quoting, conditions, loops, functions, arguments, exit codes, strict mode and a backup script.
journalctl: How to Read and Filter systemd Logs
Read systemd logs with journalctl: filter by service, time, priority and boot, follow logs live, output JSON, and limit journal disk usage on a server.
Bash String Manipulation: Substrings, Replace, Split and Trim
Manipulate strings in pure Bash: length, substrings, prefix and suffix removal, search and replace, case conversion, splitting, trimming and contains checks.
File Descriptors in Linux: stdin, stdout, stderr and Redirection
File descriptors 0, 1 and 2 explained: redirect output and errors with > and 2>&1, discard with /dev/null, inspect open FDs in /proc, avoid mistakes.
free Command: Check Memory Usage on Linux (and Read It Right)
Read Linux memory usage correctly with free: used vs available, buffers and cache, swap, continuous monitoring, and when low memory is actually a problem.
High Memory Usage on Linux: Is It a Problem and How to Fix It
Tell normal cache use from real memory pressure: read available memory, find the processes using RAM, tune PHP-FPM, MySQL and Java, and spot leaks.
chmod Command: Linux File Permissions Explained
Understand rwx permissions and octal modes like 755 and 644, use chmod with symbolic and numeric syntax, apply changes recursively and avoid chmod 777.
Set Up an NFS Server and Client on Linux (Securely)
Share directories between Linux servers with NFS: /etc/exports, client mounts and fstab, NFSv4, firewall rules, root_squash, UIDs, and VPN-only access.
SSH Jump Host with ProxyJump: Reach Private Servers via a Bastion
Reach private servers through a bastion with ssh -J and ProxyJump: ~/.ssh/config examples, multiple hops, scp and rsync via a jump host, bastion hardening.
Linux Boot Troubleshooting: GRUB, Kernel Panic, Emergency Mode
Fix a Linux server that won't boot: boot stages, GRUB rescue, kernel panics, fstab and emergency mode, full disks, and access through a VPS console.