How to use parallel ssh (PSSH) for executing ssh in parallel on a number of Linux/Unix/BSD servers

Posted on in Categories Cloud Computing, Command Line Hacks, Howto last updated April 21, 2017

Recently I come across a nice little nifty tool called pssh to run a single command on multiple Linux / UNIX / BSD servers. You can easily increase your productivy with this SSH tool.

More about pssh

pssh is a command line tool for executing ssh in parallel on some hosts. It provides specialties includes:

  1. Sending input to all of the processes
  2. Inputting a password to ssh
  3. Saving output to files
  4. IT/sysadmin taks automation such as patching servers
  5. Timing out and more

Let us see how to install and use pssh on Linux and Unix-like system.

pssh-welcome

Disabling Google Chrome PDF viewer

Posted on in Categories Howto last updated August 29, 2016

Google Chrome has “Chrome PDF Viewer” to view or open pdf files. It is an unwanted feature. I do not need it at all. I want my PDF open in Preview on a MacOS X or default pdf viewer in Linux. This feature was hidden. I want to disable it from my Google Chrome browser because it was slow scrolling with a large pdf file sizes.

Book Review: Tarsnap Mastery Online Backup For the Truly Paranoid

Posted on in Categories Amazon Web Services, Cloud Computing, Reviews last updated January 4, 2016

Tarsnap Mastery: Online Backups for the Truly Paranoid (IT Mastery) It’s always a good idea to keep backups of all of your data in multiple places. Every Linux or Unix sysadmin must master the art of backups if you want to keep your data forever. Most sysadmin recommend and follows the 3-2-1 rule:

  1. At least three copies of data.
  2. In two different formats.
  3. With one of those copies off-site.

Tarsnap is one of such off-site backup sites. It’s a secure online backup system for UNIX-like system. This service encrypts and stores data in Amazon S3. To use Tarsnap perfectly and feel secure about your backups, you need the “Tarsnap Mastery” book by Michael W. Lucas. It is no secret that I’m a big fan of his book series. Let’s see what the book is all about.

5 Awesome Open Source Cloning Software

Posted on in Categories Datacenter, Hardware, Open Source, Storage last updated November 4, 2015

Cloning is nothing but the copying of the contents of a server hard disk to a storage medium (another disk) or to an image file. Disk cloning is quite useful in modern data centers for:

  1. Full system backup.
  2. System recovery.
  3. Reboot and restore.
  4. Hard drive upgrade.
  5. Converting a physical server to virtual machine and more.

In this post, I’m going to list the Free and Open Source Software for Disk Imaging and Cloning that you can use for GNU/Linux, *BSD and Mac OS X desktop operating systems.

Book Review: The Book Of Gimp

Posted on in Categories Reviews last updated March 7, 2013

bookofgimpI usually use GIMP (the “GNU Image Manipulation Program”) for editing photos, changing colors, resizing photos, applying significant effects and more. It is a free software alternative to Adobe Photoshop. It is also quite popular with graphics artists and webmasters who wants to edit digital images. GIMP is not just a Linux specific program. It works on all leading operating systems, i.e., Mac OS X, MS-Windows and Unix variants. However, like many other powerful open source software, GIMP can be difficult to master. There are many options and plugins. So if, you are looking to learn or master the GIMP program, give The Book of GIMP a try.

Top 30 Nmap Command Examples For Sys/Network Admins

Posted on in Categories Command Line Hacks, Howto, Networking, Security last updated January 13, 2017

Nmap is short for Network Mapper. It is an open source security tool for network exploration, security scanning and auditing. However, nmap command comes with lots of options that can make the utility more robust and difficult to follow for new users.

The purpose of this post is to introduce a user to the nmap command line tool to scan a host and/or network, so to find out the possible vulnerable points in the hosts. You will also learn how to use Nmap for offensive and defensive purposes.