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)

The simple case

Frequently, string comparison is done using the test operator, [. This is ill-advised in bash, as there's a much more convenient format for string comparison, using the case statement. Here's a simple example:

testcase() {
for VAR; do
case “${VAR}” in
'') echo “empty”;;
a) echo “a”;;
b) echo “b”;;
c) echo “c”;;
*) echo “not a, b, c”;;
testcase '' foo a bar b c d

The testcase function lets us test the case statement by wrapping it in a for loop that assigns each function argument to the VAR variable, then executes the case statement. With the foo a bar b c d arguments, we can expect the following output:

not a, b, c
not a, b, c