When you need a specific Go version on Ubuntu, the default package manager often lags behind. Production systems like Kubernetes, Hyperledger Fabric, and other projects frequently require versions newer than what’s available in standard repositories. This guide covers system-level installation that allows multiple versions to coexist. Remove existing Go installations Start by cleaning up any…
View all virtual machines registered with VirtualBox: vboxmanage list vms Output example: “ubuntu-server” {a1b2c3d4-e5f6-7890-abcd-ef1234567890} “debian-test” {b2c3d4e5-f6a7-8901-bcde-f12345678901} “centos-prod” {d6c938d8-0bec-57f0-9fd3-8e395ba3d218} Each VM appears with its name and UUID. The UUID uniquely identifies the VM in VirtualBox’s database. List running VMs only See only active virtual machines: vboxmanage list runningvms This is useful when you have many VMs…
OpenSSL’s enc command supports passing passphrases programmatically rather than prompting interactively. This is essential for automation—cron jobs, CI/CD pipelines, backup scripts, and batch processing. Basic encryption with environment variables The safest approach is storing the passphrase in an environment variable, keeping it out of process listings and shell history: export PASS=examplepass openssl enc -aes-256-cbc -in…
You opened a system config file in Vim without sudo, made changes, and hit :w to save. Permission denied. Retyping everything isn’t happening. The Solution: :w !sudo tee % From Vim’s normal mode, type: :w !sudo tee % This pipes your buffer through tee running as root: :w — write the current buffer ! —…
The simplest way to display the date and time in a different timezone is with the TZ environment variable: TZ=’America/New_York’ date This temporarily sets the timezone for that single command execution without affecting your system settings. The change applies only to that invocation. Chain multiple timezone checks easily: TZ=’America/New_York’ date TZ=’Europe/London’ date TZ=’Asia/Tokyo’ date Custom…
Password-less SSH login is faster, more secure, and essential for automation. Combining it with remote command execution lets you run tasks on servers from your local machine without interactive authentication. Setting Up SSH Key-Based Authentication Generate SSH Keys First, generate an ED25519 key pair on your local machine (A): ssh-keygen -t ed25519 -C “user@hostname” -f…
By default, Python buffers stdout when it’s not connected to a terminal — typically when you redirect output to a file, pipe to another command, or run inside a container. This buffering can hide output until the buffer fills or the program exits, making debugging and log monitoring difficult. Using the flush parameter The simplest…
Files with replication factor 1 are a liability in production HDFS clusters. They have no redundancy, meaning a single node failure results in data loss. Identifying and fixing these files should be part of your regular cluster maintenance. Using the HDFS CLI The most straightforward approach is using hdfs fsck with output parsing: hdfs fsck…
Monitoring server temperatures is essential for preventing hardware damage and maintaining system stability. Linux provides several tools to query thermal sensors and identify which components are running hot. Using lm-sensors The most reliable approach is lm-sensors, a userspace tool that reads temperature data from kernel drivers: # Install lm-sensors sudo apt install lm-sensors # Debian/Ubuntu…
The screen terminal multiplexer can capture window output in several ways. Here are the most practical approaches depending on your use case. Enable logging before starting screen Start a new screen session with the -L flag to log all output to a file: screen -L -S mysession This creates a log file named screenlog.0 in…
SSHFS (SSH Filesystem) mounts a remote filesystem over SSH, letting you interact with remote files as if they were local. It uses SFTP under the hood, so no additional server configuration is needed beyond SSH access. Install SSHFS on CentOS 7 # Enable EPEL repository sudo yum install epel-release # Install sshfs sudo yum install…
Most modern systems have thermal sensors built into the CPU and motherboard. Reading these sensors is essential for monitoring system health, diagnosing performance issues, and preventing thermal throttling or hardware damage. Install lm-sensors The standard tool for reading hardware sensors on Linux is lm-sensors. Install it on your system: Debian/Ubuntu: sudo apt install lm-sensors RHEL/CentOS/Fedora:…
The usermod command is the standard tool for modifying user accounts. To change a username, use the -l (or –login) option: sudo usermod -l user1 u1 This changes the login name from u1 to user1. However, there’s an important caveat: usermod only updates the /etc/passwd file. The user’s home directory, mail spool, and other resources…
Monitoring directory growth is essential for tracking logs, temporary files, and catching runaway disk usage before it becomes a problem. Linux offers several approaches depending on whether you need simple periodic checks, interactive exploration, or event-driven monitoring. Simple periodic monitoring The watch command repeatedly runs a command at set intervals: watch -n 1 du -sh…
When you fork a repository on GitHub or GitLab, your copy diverges from the original as upstream maintainers merge new changes. To keep your fork current, you need to regularly sync it with the upstream repository. Setting up the upstream remote First, check your current remotes: git remote -v You’ll see origin (your fork). Add…
When you change thumbnail dimensions in WordPress, existing images won’t automatically resize to match. You need to regenerate them — either through a plugin or command line. Using a Plugin The easiest approach is the Regenerate Thumbnails plugin. Install it from WordPress.org, then activate it. Once activated: Navigate to Tools → Regenerate Thumbnails Click the…
Google+ shut down in 2019, so the original premise of this post no longer applies. However, the broader problem—automatically sharing blog RSS feeds across social platforms—remains relevant. Here’s how to handle RSS-to-social distribution in 2026. Modern RSS Distribution Tools For most technical blogs, you have several solid options: Zapier remains one of the most reliable…
Managing a cluster of servers, you’ll want to be notified when they come back online after restarts or unexpected reboots. Email notifications on boot let you track infrastructure changes and catch potential issues early. Using crontab @reboot The simplest approach is a crontab @reboot entry that runs once at startup. This executes before most services…
When a kernel panic occurs on a remote Linux server, manual intervention via SSH becomes impossible. The kernel can be configured to automatically reboot after a panic, allowing the system to recover without human intervention. Enable Kernel Panic Auto-Reboot The kernel.panic parameter controls this behavior. A value of 0 disables auto-reboot; any positive integer specifies…
The standard crontab -e command opens an interactive editor, which doesn’t work in automated scripts. To add crontab entries non-interactively, you need to pipe a list of cron jobs directly to crontab -. Basic approach The simplest method reads the existing crontab, appends your new entry, and writes it back: (crontab -l 2>/dev/null; echo “@reboot…