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Bash Cookbook

You're reading from  Bash Cookbook

Product type Book
Published in Jul 2018
Publisher Packt
ISBN-13 9781788629362
Pages 264 pages
Edition 1st Edition
Languages
Authors (2):
Ron Brash Ron Brash
Profile icon Ron Brash
Ganesh Sanjiv Naik Ganesh Sanjiv Naik
Profile icon Ganesh Sanjiv Naik
View More author details
Toc

Table of Contents (15) Chapters close

Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
1. Crash Course in Bash 2. Acting Like a Typewriter and File Explorer 3. Understanding and Gaining File System Mastery 4. Making a Script Behave Like a Daemon 5. Scripts for System Administration Tasks 6. Scripts for Power Users 7. Writing Bash to Win and Profit 8. Advanced Scripting Techniques 1. Other Books You May Enjoy Index

Calculating statistics and reducing duplicates based on file contents


At first glance, calculating statistics based on the contents of a file might not be among the most interesting tasks one could accomplish with Bash scripting, however, it can be useful in several circumstances. Let's imagine that our program takes user input from several commands. We could calculate the length of the input to determine if it is too little or too much. Alternatively, we could also determine the size of a string to determine buffer sizes for a program written in another programming language (such as C/C++):

$ wc -c <<< "1234567890"
11 # Note there are 10 chars + a new line or carriage return \n
$ echo -n "1234567890" | wc -c
10

Note

We can use commands like wc to calculate the number of occurrences of words, total number of lines, and many other actions in conjunction to the functionality provided by your script.

Better yet, what if we used a command called strings to output all printable ASCII strings...

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