Skip to Content
Learning Linux Shell Scripting - Second Edition
book

Learning Linux Shell Scripting - Second Edition

by Ganesh Sanjiv Naik
May 2018
Beginner content levelBeginner
332 pages
7h 28m
English
Packt Publishing
Content preview from Learning Linux Shell Scripting - Second Edition

Using exec to assign a file descriptor (fd) to file

In the Bash shell environment, every process has three files opened by default. These are standard input, display, and error. The file descriptors associated with them are 0, 1, and 2 respectively. In the Bash shell, we can assign the file descriptor to any input or output file. These are called file descriptors.

The syntax for declaring output.txt as output is as follows:

    exec fd > output.txt
  

This command will declare the number fd as an output file descriptor.

The syntax for closing the file is as follows:

    exec fd<&-
  

To close fd, which is 5, enter the following:

    exec 5<&-
  

We will try to understand these concepts by writing scripts.

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Start your free trial

You might also like

Learning Linux Shell Scripting

Learning Linux Shell Scripting

Ganesh Sanjiv Naik
Linux Shell Scripting Cookbook - Third Edition

Linux Shell Scripting Cookbook - Third Edition

Clif Flynt, Sarath Lakshman, Shantanu Tushar

Publisher Resources

ISBN: 9781788993197Supplemental Content