Blog Category: TECH 💻

How to Format a MicroSD or SD Card Using dd
Tutorial on how to format a microSD or SD flash drive using the Terminal dd command in Linux and Mac OS... continue reading

How to Format USB Flash Drive Using dd
Tutorial on how to format a USB flash drive using dd command in Linux and Mac OS... continue reading

RubyConf 2013
Arul's experiences at RubyConf 2013 in Miami Beach, Florida.... continue reading

How to Hack Your Linksys WRT54G Wireless-G Router With DD-WRT Firmware
Tutorial on how to hack your Linksys WRT54G or WRT54GL Wireless-G router and install DD-WRT firmware on it.... continue reading

How to Change User to Superuser in PostgreSQL
Blog post about how to promote regular user to superuser in PostgreSQL database.... continue reading

Bash Script to Print Sequence of Dates From Start Date to End Date
This is a shell script to print a date range or a list of dates from a starting date up to an ending date.... continue reading

How to Find and Replace Text using Vim Editor
This blog post shows you how to find and replace text using the Vim editor. It works for NeoVim and other variants as well.... continue reading

How to Generate Self-Signed SSL Certificate for 10 Years Using OpenSSL
How to create self-signed SSL certificate valid for 10 years. One line command. This uses OpenSSL to generate the SSL/TLS certificate and key.... continue reading

How to Change the Author Name and Email for Multiple Git Commits
Tutorial on how to change the author name and email address for multiple existing git commits.... continue reading

How to Disable Firefox Potential Security Risk Ahead Warning
This blog post shows how to disable Firefox's "Potential Security Risk Ahead" warnings on certain whitelisted or allowlisted websites.... continue reading

How to Monitor Let's Encrypt Certificate Expiry Dates
Bash script on monitoring local Let's Encrypt SSL certificates. This runs as a cron job.... continue reading

How to Change the Author of a Git Commit
Tutorial on how to change the author name and email address of an existing git commit.... continue reading

Mac OS X Terminal: Keyboard word shortcut
Mac Terminal shortcut to jump from word to word... continue reading

How to Generate Self-Signed SSL certificate using OpenSSL
How to create self-signed SSL certificate in one line command. This generates ssl certificate and key and uses the openssl command.... continue reading

How to Install the Latest Nginx Version 1.27 on Debian 12 bookworm
Tutorial on how to install Nginx web server Mainline version on Debian 11 bullseye or 12 bookworm.... continue reading

How to Set Up and Secure Your Linode Server
Tutorial on steps taken to set up and strenghten your new Linode server. We will show how to install Debian 12, set up firewall, accounts, etc.... continue reading

How to Import CSV and Pipe-Delimited Files to SQLite Tables
Blog post on how to import CSV and pipe-delimited files into SQLite tables.... continue reading

How to Rename Local and Remote Git Branch
Tutorial on how to rename local and remote git branches... continue reading

How to Create a Git Bare Shared Repository
This is a tutorial on how to create a shared git bare repository that others in your group can read and or write to.... continue reading

How to Install Python 3.12.5 on Debian 11 bullseye
Tutorial on installing Python 3.12.5 on Debian 11 bullseye from source. Released on August 6, 2024. Thi sblog post involves configure, make and altinstall... continue reading

How to Install Python 3.12.7 From Source
Tutorial on how to install Python 3.12.7 from source. configure, make, make install. Useful for Debian, Ubuntu, Fedora, Red Hat and other Linux systems.... continue reading

How to Install Python 3.13.0 From Source
Tutorial on how to install Python 3.13.0 from source. configure, make, make install. Useful for Debian, Ubuntu, Fedora, Red Hat and other Linux systems.... continue reading

How to find the IP address of the email sender in Gmail, Yahoo mail, Hotmail, AOL, Outlook Express, etc.
Tutorial on how to find the IP address of the email sender in Gmail, Yahoo mail, Hotmail, AOL, Outlook Express.... continue reading

Tar Files Created on macOS Display Errors When Extracting on Linux
tar.gz files seem to include extra files starting with ._. When these are extracted on Linux, a bunch of errors are displayed.... continue reading

jq Command for JSON Processing with Practical Examples
Tutorial on how to use the jq command for processing JSON input. Includes examples like getting URLs of photos taken by the Mars Perseverance Rover.... continue reading

How to Flush, Clear or Delete the DNS Cache in macOS, Windows, Linux
Different ways to flush, clear or delete the DNS cache in macOS, Windows, Linux, Google Chrome, Mozilla Firefox, Microsoft Edge and Safari.... continue reading

How to Set X-Frame-Options in Nginx, Apache, Flask and NodeJS
This blog post shows how to set X-Frame-Options in Nginx, Apache, Flask and NodeJS. Includes a complete program.... continue reading

How to Check the Debian Linux Version
Different ways to find the version of Debian GNU/Linux on your computer or server using default packages and tools.... continue reading

Email to SMS: How to send text messages for free from your email
How to send SMS for free using email. This works only in the United States and Canada, and will be extended to other countries soon.... continue reading

How to check Facebook Login History and Activity
Who last logged in to your Facebook account? Find their IP address, browser and location. If you suspect you have been hacked or someone is illegally accessing... continue reading

Nginx's "listen ... http2" directive is deprecated message
This blog post shows how to get rid of Nginx's "listen ... http2" directive is deprecated message for newer versions of Nginx.... continue reading

How to Find SSL Certificate Expiration Date With OpenSSL
This blog post shows how to check the SSL certification expiration date using openssl command. This works for both remote websites and certificates stored locally.... continue reading

How to Run or Execute Remote Linux Commands over SSH
Blog post on how to execute or run remote Linux commands over ssh. Includes command to run bash aliases over ssh.... continue reading

How to find MD5, SHA1, SHA256 and SHA512 Checksums Of String
Blog post on how to find MD5, SHA1, SHA256 and SHA512 checksums from your computer without having to use any online tools.... continue reading

How to Remove File Attribute 'Where From' After Downloading on Mac
If you download a PDF or any other file from the Internet on your Mac, it may add a new attribute called "Where from" that shows the URL from where it was downloaded. This blog post shows how to get rid of it on macOS.... continue reading

How to encrypt and decrypt text files using Vim editor
This blog post shows you how to encrypt and decrypt text files using the built-in encryption support in the Vim editor. vim -x... continue reading

How to Make DNS Queries over HTTPS using Curl
Tutorial on how to make DNS queries over HTTPS using the DoH protocol. You do not need dig installed. ... continue reading

How to Download and Extract URLs from Sitemaps using the Command Line
This blog post shows you how to download and extract URLs from a Google XML sitemap and do other things from the command line. We will use curl and wget.... continue reading

Why is my IP Address Temporarily Blocked?
Sometimes, when you go to a website, you may get a message saying, 'Your IP address has been temporarily blocked' or something similar. This article explains why it happened and what steps you can take to resolve it and access those websites again.... continue reading

How to Enable HSTS in Nginx, Apache, Flask, NodeJS
This blog post shows how to enable HSTS in Nginx, Apache, Flask and NodeJS.... continue reading

Why Are There Traffic Advice 404 Errors in My Web Server Logs?
This blog post shows you how to handle 404 not found errors for the file /.well-known/traffic-advice in your Nginx or Apache web server logs.... continue reading

Grep command in Linux and Unix with examples
Grep command in Linux and Unix with examples related to practical use, at work.... continue reading

How to find IP addresses from a hostname
This blog post shows how to get the IP addresses associated to a domain name using Linux or Unix.... continue reading

How to install Python packages offline
This tutorial shows you how to install Python packages if your computer is offline or the firewall prevents connection to pypi.org.... continue reading

How to install and setup a Minecraft Server
Tutorial on installing and setting up a Minecraft server on your computer.... continue reading

Modify column name in SQLite
Blog post on how to change a column name or modify column data type in SQLite.... continue reading

Free Heroku Alternatives
Heroku is removing their free product plans and inactive accounts. This is a list of Heroku alternatives with free plans. Includes AWS, Google App Engine (Google Cloud) and others.... continue reading

What is a MAC Address? Everything about MAC addresses
Introduction to MAC addresses. MA-L, MA-M and MA-S blocks, OUI, OUI-36, IAB, MAC address in binary, MAC address cloning.... continue reading

What is an IP Address?
Basic article about IP addresses, IPv4 and IPv6 addresses, subnetting, broadcast and multicast, IP addresses in email headers and so on. This was written from a beginner's perspective.... continue reading

How to see your Yahoo! Mail log activity
This is how to check if your Yahoo! Mail has been compromised or hacked. You can see the history of the last 20 login attempts... continue reading

How to secure your Facebook account with two-factor authentication
Tutorial on how to secure your Facebook account using two-factor authentication or 2FA.... continue reading

Install Visual Studio Code for Python development
Tutorial on how to install Visual Studio Code for development in Python. This includes installing of plugins.... continue reading

Make FiOS gateway use OpenDNS
Tutorial on how to use OpenDNS servers on your Fios gateway.... continue reading

Full-text Search Using PostgreSQL
Tutorial about using full-text search using PostgreSQL 10 and above.... continue reading

How to Unarchive Multiple .7z Files
How to Extract Multiple .7z Files Using the Command Line... continue reading

Parsing Web Server Logs
Different ways of parsing web server logs. Finding unique IP addresses of visitors.... continue reading

Various MySQL commands
MySQL commands for the client command line... continue reading

Change the server date and time in CentOS
Change the server date and time in CentOS... continue reading

Patching glibc CVE-2015-7547 Vulnerability
How to patch the glibc vulnerability CVE-2015-7547 in CentOS, Ubuntu and Debian... continue reading

Disabling SELinux in CentOS 7
Nginx does not run with SELinux enabled. I had to disable it to allow the nginx process to run.... continue reading

Stop Photos app from opening automatically when an iPhone or iPad is connected to the Mac
How do I disable the Photos app from automatically opening when my iPhone or iPad is connected to the Mac.... continue reading

Stop Image Capture from opening when a new device is connected
How do I disable the Image Capture app from automatically opening when my iPhone or iPad is connected to the Mac.... continue reading

Install Ruby on Rails from source
Article about installing Ruby from source and Rails for Mac OS, Debian and CentOS.... continue reading

How to find UDID of iPhone, iPad or iPod Touch
Short tutorial on how to find the unique device identifier (UDID) of your iOS device - iPhone, iPod Touch or iPad... continue reading

How to fix the shellshock bash bug vulnerability in bash shell
How to fix the shellshock bash bug vulnerability in bash shell... continue reading

How to install Windows 7 on VirtualBox
Guide on how to install Windows 7 on VirtualBox virtual machine.... continue reading

Watch Starwars on the Terminal
Watch Starwars on the Terminal. Using Mac Terminal, PuTTY or any Linux/Unix console.... continue reading

Profile Picture, Cover Photo and Other Image Dimensions
Comprehensive list of dimensions of photos and images in Facebook, Twitter, Google+, LinkedIn and major social media websites.... continue reading

VirtualBox: How to access guest (CentOS) webserver from the host (Mac OS X) on NAT
This is an article how to access guest (CentOS) webserver from the host (Mac OS X) using NAT and Host-Only networks.... continue reading

Samsung Series 3 laptop: How to get BIOS boot menu to show DVD and USB devices
How to get boot menu to show DVD and USB devices in Samsung Series 3 laptops... continue reading

How to reset your Verizon FiOS router password
Basic tutorial on reseting your Verizon FiOS router password to the default one.... continue reading

How to reset admin password on Mac OS X
Tutorial to reset the admin password on Mac OS X (Leopard or Snow Leopard).... continue reading

How to create an SSH connection without a password
This tutorial shows you How to create an SSH connection without a password. Useful for ssh, scp and cron jobs that require password-less logins.... continue reading

I cannot insert a CD or DVD into my MacBook's slot load SuperDrive
How to insert a CD/DVD into a troublesome superdrive in your MacBook... continue reading

HISTORY shell variable management in Unix/Linux
HISTORY shell variable management in Unix/Linux.... continue reading

Convert docx to doc in Mac OS X Snow Leopard or Leopard
Convert docx to doc in Mac OS X Snow Leopard or Leopard... continue reading

How to eject CD/DVD from your MacBook or iMac
How to eject CD/DVD from your MacBook or iMac. drutils, diskutil, drag-drop to trash can... continue reading

How to rename multiple files in Unix or Linux
How to rename multiple files in Unix or Linux from the prompt.... continue reading

Play Prince of Persia on Ubuntu Linux using DOSBox
How to play Prince of Persia and other games on Ubuntu Linux using DOSBox.... continue reading

Detect iPad in PHP, Perl, JavaScript, Nginx, Apache, Lighttpd
How to detect if the visitor is using an iPad. Programming in PHP, Perl and JavaScript. Server configuration for nginx, apache, lighttpd. .... continue reading

Copy specified directories from one location to another
... continue reading

Installing Ubuntu Linux in VirtualBox
Installing Ubuntu Linux in VirtualBox. Linux guest on Windows host.... continue reading

Cron Task Scheduling
How to schedule tasks with cron.... continue reading

Quick references for tar, gzip and bzip2
Quick reference commands to using tar, gzip and bzip2. Archive and uncompress tar, tar.gz and tar.bz2 files.... continue reading

(128)Network is unreachable: connect to listener
(128)Network is unreachable: connect to listener. Apache error.... continue reading

Unix find command with examples and common usage
Unix find command with examples and common usage.... continue reading

Configuring Nginx to forward PHP requests to Apache mod_php
HOWTO: Nginx to forward PHP requests to Apache mod_php.... continue reading

How to forward Nginx Perl requests to Apache mod_cgi
How to forward Perl (.pl) requests in Nginx web server to Apache mod_cgi.... continue reading

Configuring Nginx to include PHP FastCGI support
How to configure Nginx to include PHP FastCGI support.... continue reading

Configuring Nginx web server
Configuring Nginx web server. nginx.conf tweaks.... continue reading

How to rescue your files if Windows is busted
Rescue your important files if Windows is corrupted. Burn to CD or transfer to a remote location using System Rescue CD, Scp,Xfburn,gparted.... continue reading

Solaris Commands
Some frequently used Solaris commands. Useful for System Administrators.... continue reading

How to remove CTRL M characters
This is a tutorial on how to remove the Control-M character ^M at the end of line. This usually happens when you save the file in Windows.... continue reading

How to use the HTTP commands GET and HEAD
How to use GET and HEAD commands on the command line.... continue reading

How to compress your webpages
How to compress webpages using gzip or deflate. Apache, Nginx, Lighttpd web servers.... continue reading

Test for SSL version
How to test for SSL version.... continue reading

How to save a document or webpage as PDF
How to save a document DOC, PUB, webpage, etc as PDF.... continue reading

apt-get and dpkg commands in Debian
Some useful apt-get commands and resources.... continue reading

How to handle X11 Forwarding using SSH
How to handle X11 Forwarding using SSH and Xming.... continue reading

How to install Ubuntu 7.10 Edition v1.0 on your Sony PSP
Install Ubuntu 7.10 version 1.0 on your Sony PSP.... continue reading

How to set up your own website with domain hosting
How to get domain hosting and set up your own web site.... continue reading

Customize Your Bash Prompt
... continue reading

Windows Hacks, Tips and Tricks
This page contains Windows hacks and many tips on how to do things that are traditionally not displayed in the usual options in Windows.... continue reading

SSI Includes
How to embed CGI files and other files in HTML files using SSI includes.... continue reading

.htaccess tutorial with mod_rewrite
Using and editing .htaccess file for configurations. .... continue reading

Installing X Window on Debian
Installing X Window and Window Manager on Debian. Xorg.... continue reading

My Linux Settings and Configuration Files
My Linux box settings are listed here, they include configuration files tcshrc, xmodmap, grub.conf, init.d files.... continue reading

Changing file system from Ext2 to Ext3 in Debian
How to upgrade file system in Linux, How to install Debian Linux on your computer.... continue reading

File transfer using Linux or Unix
File transfer programs to use in Linux or Unix.... continue reading

Installing Applications and Servers in Debian GNU/Linux
Installing Applications and Servers in Debian Linux.... continue reading

How to uninstall the Microsoft Java Virtual Machine (JVM)
How to uninstall the Microsoft Java Virtual Machine (JVM).... continue reading

Upgrading the kernel in Debian
Upgrading the kernel to 2.6.16.x in Debian Linux.... continue reading

How to Dual Boot with Linux and Windows XP
How to dual boot Windows XP with Linux. How to remove Grub and LILO.... continue reading

How to change boot sequence between Windows and Linux
Changing boot sequence between Windows and Linux.... continue reading

How to install Debian GNU/Linux on your computer
How to install Debian GNU/Linux on your computer.... continue reading

Cell phone secrets and tricks for Sony Ericsson T610
How to get more out of your Sony Ericsson T610 cell phone: unlocking, tricks, shortcuts, IMEA code.... continue reading

Emacs Commands
Summary of essential emacs commands. Useful for beginners and regular users.... continue reading

Important and useful Linux and Unix commands
Some important and useful commands I learnt while installing Linux.... continue reading