Unix

What Is UNIX?

UNIX is a multi-user, multi-tasking Network Operating System.

UNIX was first developed in 1969 by AT&T for a DEC PDP platform and throughout the 80s was ported to many different hardware platforms, made possible through licenses to the source code. AT&T also made their source code available to some US universities, one of which was Berkeley University, and they developed their instances of UNIX.

By the mid 80s there were two main variants of UNIX source code available to computer manufacturers:

Searching for Lines Containing Patterns 

The grep command is perfect in these situations and we explore some of it’s capabilities here.

Linux Systems offer an X Windows interface which can make changing system settings and configuration pretty straight forward, but what if you remotely log in via a Secure Shell (SSH) session using a tool such as putty?

Here is how to change the system date and time and the hostname from the command line.

Changing The Date & Time in Linux

The date command can be used by root to change the system date and time.

Creating UNIX & Linux Piped Commands

UNIX and Linux offer a very powerful feature know as pipes. It is often possible to carry out really complicated tasks without the need for shell scripting, variables, loops, etc.

Take the following example, which creates a dictionary file from a text document, but excludes one and two letter words:

tr -cs "[a-z][A-Z]" "[\012*]" < readme.txt | sort -uf | tr "[A-Z]" "[a-z]" | egrep -v "(^.$|^..$)" > dictionary

One command line that is comprised of five separate steps:

So How Old is Unix?

And how old is Windows (Server version)? 23 years old.

UNIX is twice the age of Microsoft Windows (Server version)!