Slash notation lookup table

Total-addresses: how many unique addresses can be represented. To determine how many are available to be assigned to devices you need to subtract 2 from the provided number to allow for the ‘network’ and ‘broadcast’ address. A further one of these may need to be assigned to a router. Net bits Subnet mask Total-addresses /20 4096 /21 […]

Introduction to APT (advanced package Tools)

Advanced Packaging Tool Ubuntu — and all Debian-based distros — includes the Advanced Packaging Tool (APT), which can be used to easily download and install software for the operating system. This article looks at APT, and how it is used. Topics : Table of Contents Installing Software on a Computer Installing Software on Windows Installing Software on […]

Introduction to Yum

1. Introduction   Yum is a tool for automating package maintenance for a network of workstations running any operating system that use the Red Hat Package Management (RPM) system for distributing packaged tools and applications. It is derived from yup, an automated package updater originally developed for Yellowdog Linux, hence its name: yum is “Yellowdog Updater, Modified”. Yup was originally […]

The /etc/passwd File Format

The /etc/passwd file stores essential information, which is required during login i.e. user account information. /etc/passwd is a text file, that contains a list of the system’s accounts, giving for each account some useful information like user ID, group ID, home directory, shell, etc. It should have general read permission as many utilities, like lsuse […]

Tar a folder or entire system through ssh

We all had the problem of needing to backup a folder or an entire system from a machine before decommissioning or as a postfix backup solution only to find tarring aint gonna work cause you have very little space left. Also there are folders you want to avoid tarring since they contain logs or system […]

The Linux Conundrum

A large company, was taking over our smaller company and they were on a trend to replace Linux and Java with MS Windows  ®  and ASP.NET. When the CIO was asked why not go the other way since arguably our smaller company was more advanced put plainly his answer “Linux and Java guys are so hard […]