theshell.ch/site/pages/scripts/0-base-commands.html

---
layout: page
category-page: scripts
category-title: Scripting
tags: command base echo cat grep
author: Dario Rasic
title: Script  Base Commands
next-page: pages/scripts/1-variables.html
---
<!-- Echo command text -->
<h3>Echo</h3>
<p>This command prints its entire argument as output on the command-line.<br>
    It can be used with variables, like in the following example:<br>

<pre>
example="this is an example"

echo $example
    this is an example
</pre>

<!-- Cat command text -->
<h3>Cat</h3>

This command prints the content of a certain file as output on the
command-line.<br>

For example, we could imagine a simple text file in nano named "Hello", which contains
the line "Hello World".<br>
So, our command example will look like this:<br>

<pre>
nano Hello
cat Hello
    Hello World
</pre>


<!-- Grep command text -->
<h3>Grep</h3>

This one behaves very similarly to the previus one, but in this case it prints only
the lines matching a certain pattern.<br>
In this we could imagine a certain text file "animals", which contains a list of animal-names.

If we want to select only the animals whose name begins with the letter "d", we will write this:<br>

<pre>
grep "D" animals
    Deer
    Dragon
    Dinosaur
    Dog
    Dolphin
</pre>