dexter's blog

How to use regular expressions in Linux?

  • Posted on: 1 May 2020
  • By: dexter

Regular Expression or regex, as assumed by many, is not a tool or software. Regular expression is a sequence of characters that define a search pattern. This was given back in 1950 by  mathematician Stephen Cole Kleene who then formalized the description of a regular language

Adding multiple users to Linux using BASH

  • Posted on: 29 April 2020
  • By: dexter

Some or the other time as a sys admin you will come across a need to add multiple users to your Linux system. So the question is how to do the same.

Let us see how we can do the same in this post.

We will assume that N number of users are to be added with a standard prefix or suffix and values incrementing with numbers. e.g.  employee27... emp28.. etc

The command to add a user is useradd

The command can be simply run as:

How to check previous command status in BASH?

  • Posted on: 23 April 2020
  • By: dexter

BASH is the default shell in GNU/Linux systems.  While writing BASH scripts sometimes it become necessary to take action based upon the success of previous command. So how do we do this.

First we need to understand that almost every command that is run once completed returns a exit code, 99% of commands just use 0 for success, 1 for failure. Without getting into other details, lets see how we can use this value.

GNU/Linux: Understanding important installation steps

  • Posted on: 19 April 2020
  • By: dexter

The hard drive need to be partitioned properly before you can install GNU/Linux system, some time if you want to keep the existing OS, you will need to resize the existing parts to make space for the new OS

GNU/Linux Advantages and Pre-Install checklist

  • Posted on: 12 April 2020
  • By: dexter

The Linux kernel is widely used now a days to for a usable system, generally what people refer as an OS, which we prefer to call as GNU/Linux distribution.  Linux itself is available as a Free Software as well as most of the GNU/Linux Distributions are also available under similar FOSS licenses.