2017-01-27 09:17 pm

Installing Kernel-based Virtual Machine (KVM) on Ubuntu 16.04 server



Kernel-based Virtual Machine (KVM) is a virtualization infrastructure for the Linux kernel that turns it into a hypervisor. It was merged into the Linux kernel mainline in kernel. It is now part of Linux kernel itself. It consists of a loadable kernel module, kvm.ko, that provides the core virtualization infrastructure and a processor specific module, kvm-intel.ko Intel or kvm-amd.ko for AMD cpu.


=> Read more: How to install KVM on Ubuntu 16.04 LTS Headless Server
2017-01-27 04:51 pm

How to ppen a file in a tab in vim in readonly mode on Linux, MacOS and Unix system

Want to open a file in read-only mode on Unix, try:
vim -M file
OR open a tab in read-only mode:
: view file



More info: Open a file or a tab in vim in readonly mode
2017-01-26 04:20 pm

How To Fix SSH "WARNING: UNPROTECTED PRIVATE KEY FILE!" on Unix/MacOS/Linux

If you are getting this error then you probably reset the permissions on your keys:

chmod 0400 ~/.ssh/key
chmod 0700 ~/.ssh/
ssh -i ~/.ssh/key user@server




More info: Fixing ssh error.
2017-01-24 07:36 pm

Want to flush the content of memcached server using bash on Linux/Unix?



You type the following command to flush the content of memcached server:
echo flush_all >/dev/tcp/127.0.0.1/11211

=> More commands and options here about the same.
2017-01-24 05:02 pm
Entry tags:

curl ignore invalid ssl certificate warning



Want to ignore SSL warning with curl command on Linux/Unix/MacOS? Try:

curl -k url
curl -k -I url


More info: cURL Ignore SSL Certificate Warnings
2017-01-24 03:22 pm

{HOWTO} Limiting SSH Connections with ufw on Linux


How do I limit ssh connection attempts using UFW (Uncomplicated Firewall) on Ubuntu or Debian Linux server?

UFW means Uncomplicated Firewall. It defaults on Ubuntu and can be installed on other Linux distros such as Arch Linux, Debian and more.

Read more here...
2017-01-23 11:50 pm

How to install LXD container under Linode KVM Cloud server

For security and ease of admin, I want to install LXD on my cloud server either powered by XEN or KVM. How do I install LXD on Ubuntu Linux server powered by KVM virtualization technology?

In this quick tutorial you will learn how to install the latest stable version of LXD container under KVM cloud server hosted at Linode for security mechanism on Ubuntu Linux 16.04.xx LTS server.
2017-01-23 11:26 pm

The Awk Programming Language for all {PDF version}

AWK is a programming language designed for text processing and typically used for a data extraction and reporting tool. It is a standard feature of Linux, FreeBSD, OpenBSD, MacOS and most Unix-like systems.



Download: The AWK programming book (PDF version)
2017-01-23 05:26 pm

Directly attach screen/tmux over ssh session & save a useless parent bash process:

Run the following command:

ssh -t box screen -r
ssh -t box tmux a
ssh -t user@server screen -r
ssh -t user@server tmux a

2017-01-23 04:12 pm
Entry tags:

How to determine if a bash variable is empty in a Linux or Unix?



My shell script depends upon user input. How do I find out if a variable called $_JAIL path is empty under a Linux / Apple OS X / Unix like operating systems? What is the best way to determine if a variable in bash is empty?

Pass the -z option to the if command or conditional expression.

Read more here