Articles by Dejan Panovski
Email Authentication Explained: SPF, DKIM, and DMARC
SPF, DKIM, and DMARC help prevent domain spoofing. See how each check works, what DMARC alignment requires, and how to verify the DNS records with dig.
How to Unzip a .gz File in Linux
Unzip a .gz file in Linux with gzip or gunzip, keep the original file when needed, and extract .tar.gz archives with tar.
Redirect HTTP to HTTPS in Nginx
How to redirect HTTP to HTTPS in Nginx using a separate server block with a 301 redirect, for a single site or all sites on the server.
sha256sum and md5sum: Verify Checksums in Linux
Check a file's SHA-256 or MD5 checksum in Linux: generate digests with sha256sum and md5sum, verify SHA256SUMS lists with -c, and confirm ISO downloads.
What Is stdin, stdout, and stderr in Linux
stdin, stdout, and stderr are Linux's three standard streams. See how file descriptors 0, 1, and 2 connect commands to terminals, files, and pipes.
How to Set Environment Variables in Linux
Set, list, and make environment variables permanent in Linux. Covers shell vs environment variables, export, printenv, and persistent config in ~/.bashrc and /etc/profile.
How to Configure Networking with Netplan on Ubuntu
Configure Ubuntu networking with Netplan using practical YAML examples for DHCP, static IP addresses, DNS, Wi-Fi, bridges, and safe remote changes.
How to Enable and Disable Root User Account in Ubuntu
This guide explains how to enable and disable the root user account in Ubuntu using the passwd command, and covers safer alternatives like sudo -i and su -.
Nginx Reverse Proxy: How to Configure proxy_pass and Headers
Configure Nginx as a reverse proxy with proxy_pass and proxy_set_header, including client IP forwarding, websockets, TLS termination, and common fixes.
less Command in Linux: Navigate and Search Files
How to use the less command in Linux to view files page by page, search for text, follow log files in real time, and navigate with vi-style key bindings.
How to Change User Password in Ubuntu
Change a user password in Ubuntu from the command line with passwd, or through the GNOME Settings app. Covers your own account and other users.
Docker: List Running and Stopped Containers
Use docker container ls and docker ps to list running and stopped containers, print names and IDs, filter results, and check Docker Compose projects.
passwd Command in Linux: Change User Passwords
Change your own, another user's, or the root password in Linux with the passwd command. Covers password expiry with chage, forcing a change at next login, and account locking.
tree Command in Linux: Display Directory Structure
The tree command lists directories recursively as an indented tree. This guide covers installation, depth limits, filtering, sizes, and saving the output.
How to Read a File Line By Line in Bash
Read a file line by line in Bash using a while loop and the read command. This guide covers IFS splitting, mapfile arrays, command output, and common pitfalls.
How to Encrypt and Decrypt Files with GPG
Encrypt files with GPG using a passphrase or a key pair, share encrypted files with other people, protect whole directories, and decrypt safely in scripts.
curl Command in Linux: Usage and Examples
The curl command transfers data to and from servers using HTTP, HTTPS, FTP, and other protocols. This guide covers downloads, headers, POST requests, verbose debugging, proxies, and API usage.
nohup Command in Linux: Background Jobs and Output
nohup keeps commands running after logout. The 'appending output to nohup.out' message is not an error. This guide covers background jobs, 2>&1 redirection, and stopping processes.
tmux Command in Linux: Sessions, Windows, and Panes
The tmux command lets you run persistent terminal sessions with multiple windows and panes. This guide covers creating and managing sessions, splitting panes, copy mode, and configuration.
strace Command in Linux: Trace System Calls
Use the strace command to trace system calls and signals on Linux, debug why a program fails, find missing files, and measure where a process spends its time.
