Gain insights into the power of the command line. Learn about Linux BASH through theoretical and practical exercises, mastering essential concepts and commands for efficient programming.

Ever wondered why command line is still in use even when there are hundreds of human-friendly GUI’s and tools available? Everyone in the programmer's world would agree on one thing: Command Line is far more powerful than any GUI. It provides a richer experience in terms of speed and expressiveness.

For beginners, it might be hard to appreciate its beauty and a little challenging to shift from an interactive interface to a blank box with just a “$” sign showing that keeps prompting the user to enter complex commands if you want to get something done. This is why we felt the need to build a course which could help the user overcome his/her fear of using the terminal (we have all been there).

The objective of this course is to help you get a strong grip over Linux, mainly focusing on BASH. You will be covering both, the theoretical and practical sides. First, you will learn a bunch of concepts necessary to understand things and then study some nifty commands to get useful things done out of them.

Bash for Programmers

# uniq 
## Definition:
`uniq` command in bash is a command line utility to filter and view multiple repeated lines.

> This command works on _adjacent comparison lines_ so it is often combined with the **sort** command.


It can be used to:
- remove duplicates.
- show only repeated lines.
- show a count of repeated occurrences.
- comparing particular fields and ignoring certain inputs.

## Syntax:
```css
uniq [option] [input[output]]
```

## Options:
| **Option** | **Description** |
| --- | --- |
| -c | Prefix lines with a number showing how many times they occurred. |
| -d | Only print duplicated lines. |
| -u | Only print unique lines. |
| -z | End lines with 0 byte (NULL), instead of a newline. |
| -w | Compare no more than **N** characters in lines.|
| -i | To perform case-insensitive comparisons. |
| -f | To avoid comparing first **N** fields of a line before determining uniqueness. (_**Field** is a set of characters delimeted by a white space._) |
| -s | To avoid comparing first **N** characters before determining uniqueness. |

## Examples:
- To display repeated lines:

Review different ways to search for repeated lines in a text or a file.

Introduction to Bash

Navigation Commands

File Manipulation Commands

Permission Commands

Filtering & Searching Commands

System & Process Commands

Variables and Environment

An Overview of Commands

Filtering Repeated Lines Out

uniq

Definition: