Book Image

Hands-On Data Science with the Command Line

By : Jason Morris, Chris McCubbin, Raymond Page
Book Image

Hands-On Data Science with the Command Line

By: Jason Morris, Chris McCubbin, Raymond Page

Overview of this book

The Command Line has been in existence on UNIX-based OSes in the form of Bash shell for over 3 decades. However, very little is known to developers as to how command-line tools can be OSEMN (pronounced as awesome and standing for Obtaining, Scrubbing, Exploring, Modeling, and iNterpreting data) for carrying out simple-to-advanced data science tasks at speed. This book will start with the requisite concepts and installation steps for carrying out data science tasks using the command line. You will learn to create a data pipeline to solve the problem of working with small-to medium-sized files on a single machine. You will understand the power of the command line, learn how to edit files using a text-based and an. You will not only learn how to automate jobs and scripts, but also learn how to visualize data using the command line. By the end of this book, you will learn how to speed up the process and perform automated tasks using command-line tools.
Table of Contents (8 chapters)

It's the end of the world as we know it while and until

Let's explore two more options for assisting with iteration. The while construct allows for the repetitive execution of a list or set of commands as long as the command that controls the while loop exits successfully. Let's see an example:

Let's say I wanted to print the "hello!" string four times in a script—no more and no less. We can do so with the following:

Let's save and run this script to see what happens.

Don't forget to chmod -x these scripts to make them executable.

Executing the script produces the following:

Notice that, in the script, we created a variable called i="0". This sets the i variable to zero. Do you see the while [ $i -lt 4 ] block? This allows us to run the loop as the i variable is less than the 4 integer. Go ahead and play around with this...