Book Image

Linux Shell Scripting Cookbook, Second Edition - Second Edition

Book Image

Linux Shell Scripting Cookbook, Second Edition - Second Edition

Overview of this book

The shell remains one of the most powerful tools on a computer system — yet a large number of users are unaware of how much one can accomplish with it. Using a combination of simple commands, we will see how to solve complex problems in day to day computer usage.Linux Shell Scripting Cookbook, Second Edition will take you through useful real-world recipes designed to make your daily life easy when working with the shell. The book shows the reader how to effectively use the shell to accomplish complex tasks with ease.The book discusses basics of using the shell, general commands and proceeds to show the reader how to use them to perform complex tasks with ease.Starting with the basics of the shell, we will learn simple commands with their usages allowing us to perform operations on files of different kind. The book then proceeds to explain text processing, web interaction and concludes with backups, monitoring and other sysadmin tasks.Linux Shell Scripting Cookbook, Second Edition serves as an excellent guide to solving day to day problems using the shell and few powerful commands together to create solutions.
Table of Contents (16 chapters)
Linux Shell Scripting Cookbook
About the Authors
About the Reviewers

Grabbing information about the terminal

While writing command-line shell scripts, we will often need to heavily manipulate information about the current terminal, such as the number of columns, rows, cursor positions, masked password fields, and so on. This recipe helps in collecting and manipulating terminal settings.

Getting ready

tput and stty are utilities that can be used for terminal manipulations. Let us see how to use them to perform different tasks.

How to do it...

There are specific information you can gather about the terminal as shown in the following list:

  • Get the number of columns and rows in a terminal by using the following commands:

    tput cols
    tput lines
  • To print the current terminal name, use the following command:

    tput longname
  • To move the cursor to a 100,100 position, you can enter:

    tput cup 100 100
  • Set the background color for the terminal using the following command:

    tputsetb n

    n can be a value in the range of 0 to 7.

  • Set the foreground color for text by using the following command:

    tputsetf n

    n can be a value in the range of 0 to 7.

  • To make text bold use this:

    tput bold
  • To start and end underlining use this:

    tput smul
    tput rmul
  • To delete from the cursor to the end of the line use the following command:

  • While typing a password, we should not display the characters typed. In the following example, we will see how to do it using stty:

    echo -e "Enter password: "
    stty -echo
    read password
    stty echo
    echo Password read.


    The -echo option in the preceding command disables the output to the terminal, whereas echo enables output.