Book Image

Linux Command Line and Shell Scripting Bible - Third Edition

By : Richard Blum, Christine Bresnahan
Book Image

Linux Command Line and Shell Scripting Bible - Third Edition

By: Richard Blum, Christine Bresnahan

Overview of this book

The Linux command line enables you to type specific shell commands directly into the system to manipulate files and query system resources. Command line statements can be combined into short programs called shell scripts, a practice increasing in popularity due to its usefulness in automation. Linux is a robust system with tremendous potential, and Linux Command Line and Shell Scripting Bible opens the door to new possibilities. Linux Command Line and Shell Scripting Bible is your essential Linux guide. It contains new functional examples that are fully updated to align with the latest Linux features. Beginning with command line fundamentals, the book moves into shell scripting and shows you the practical application of commands in automating frequently performed functions. This book is a complete guide providing detailed instruction and expert advice working within this aspect of Linux. Whether used as a tutorial or as a quick reference, this book contains information that every Linux user should know.
Table of Contents (34 chapters)
2
Part I: The Linux Command Line
13
Part II: Shell Scripting Basics
20
Part III: Advanced Shell Scripting
28
Part IV: Creating Practical Scripts
32
End User License Agreement

Practical Example

File redirection is very common both when reading files into scripts and when outputting data from a script into a file. This example script does both of those things. It reads a .csv-formatted data file and outputs SQL INSERT statements to insert the data into a database (see Chapter 25).

The shell script uses a command line parameter to define the name of the .csv file from which to read the data. The .csv format is used to export data from spreadsheets, so you can place the database data into a spreadsheet, save the spreadsheet in .csv format, read the file, and create INSERT statements to insert the data into a MySQL database.

Here's what the script looks like:

$cat test23
#!/bin/bash
# read file and create INSERT statements for MySQL
outfile='members.sql'
IFS=','
while read lname fname address city state zip
do
   cat >> $outfile << EOF
   INSERT INTO members (lname,fname,address,city,state,zip) VALUES
('$lname', &apos...