Shell Script Wrapper Examples: Enhance the Ping and Host Commands

Posted on in Categories Linux, Shell scripting, UNIX last updated January 31, 2016

Shell script wrappers can make the *nix command more transparent to the user. The most common shell scripts are simple wrappers around third party or system binaries. A wrapper is nothing but a shell script that includes a system command or utility.

Linux and Unix like operating system can run both 32bit and 64bit specific versions of applications. You can write a wrapper script that can select and execute correct version on a 32bit or 64bit hardware platform. In cluster environment and High-Performance computing environment you may find 100s of wrapper scripts written in Perl, Shell, and Python to get cluster usage, setting up shared storage, submitting and managing jobs, backups, troubleshooting, invokes commands with specified arguments, sending stdout to stdout and stderr to stderr and much more.

In this post, I will explains how to create a shell wrapper to enhance the basic troubleshooting tool such as ping and host.

HowTo: Use OpenBSD In the Corporate Environment

Posted on in Categories OpenBSD last updated April 20, 2011

OpenBSD has a reputation for high security and difficult operating systems for new user. But, some orginsations are using OpenBSD for everything including firewall, servers and desktop computers. This is quite impressive, from the article:

So our paid job is hacking on and deploying, maintaining, supporting… OpenBSD installations. We are also required to hack on things that can be merged back into OpenBSD itself and when it’s not possible, then we change what we did so that it can be. Of course some developments are very specific to what we do and have no place in the project’s CVS tree.

So, amongst other services, we set up and maintain several 100% OpenBSD-based infrastructures (going from the entry site firewall to the secretary’s workstation) and this is what I’m going to talk about here.

As a side note, it is important to know that we are working exclusively for Fortune 500 companies (each operating in totally different and unrelated sectors).

Read more: A Puffy in the corporate aquarium.

Firewall Builder: Convert Linux Iptables Configuration to OpenBSD and PF

Posted on in Categories Iptables, Linux, OpenBSD, Security last updated March 25, 2010

Lets see how much effort it is going to take to convert this configuration to entirely different firewall platform – PF on OpenBSD. There are different ways to do this. I could make a copy of each member firewall (linux-test-1 and linux-test-2), set platform and host OS in the copy to PF and OpenBSD and then create new cluster object. This would be a sensible way because it preserves old objects which helps to roll back in case something does not work out. However, to make the explanation shorter, I am going to make the changes in place by modifying existing objects.

OpenBSD foundation announced

Posted on in Categories OpenBSD, UNIX last updated July 26, 2007
OpenBSD foundation announced

Good news from OpenBSD project. The OpenBSD Foundation is pleased to announce today it has completed its organization as a Canadian federal non-profit corporation and is ready for public interaction.

The OpenBSD Foundation is a Canadian not-for-profit corporation which exists to support OpenBSD and related projects such as OpenSSH, OpenBGPD, OpenNTPD, and OpenCVS. While the foundation works in close cooperation with the developers of these wonderful free software projects, it is a separate entity.

However this may turn down a few people:

We are not a registered charity, in the sense that we do not issue tax deductible receipts. The reporting overhead (accounting and legal costs) to operate a registered charity in Canada is prohibitive without a sizable revenue stream. Currently, this would divert a great deal of resources that could be better utilized in helping build good free software. We do issue receipts (not tax deductable) for all donations.

Nevertheless it is a good move in right direction.

=> The OpenBSD Foundation