Machine Learning: Hands-On for Developers and Technical Professionals

Appendix CUseful Unix Commands

Regardless of the operating system you use on a daily basis, there's nothing wrong with learning some handy Unix commands. The commands covered in this section will help you on the day-to-day tasks of quickly testing, parsing, and searching through your text data.

If you're a Windows user, you can still join in by downloading Cygwin, which is a Unix shell command interpreter. Cygwin is a shell that sits on top of the Windows Command application and behaves like it's a Unix install.

Some of these commands will appear from time to time in the chapters of this book, especially in Chapters 9 and 10, so it's worth reviewing them now. Experiment with them and study the output so you have an idea of what to expect.

Using Sample Data

Before you get started with the tools, you need some sample data. With a text editor, type out the following lines and separate each value with a tab.

987    1391548780   hhh bbb
988    1391548781   sda jjj
989    1391548782   asd asd
990    1391548783   gjh jkl
991    1391548784   abc abc
992    1391548785   ghj gjh
993    1391548785   hhh bbb
994    1391548785   sda jjj
995    1391548786   asd asd
996    1391548787   gjh jkl
997    1391548787   abc abc
998    1391548787   ghj gjh

Name the text file text.txt, and then you can follow along with the following commands and see the output. The sample data is basically comprised of a unique id, a timestamp, and some text. It's the sort of thing you would see within a database table but is output as text. This example uses a tab delimiter, ...