file descriptor

Welcome to today's deep dive into an effective but less commonly known bash scripting technique. Today, we're exploring the use of the exec {fd}<>file construct, which opens up powerful possibilities for file handling in bash scripts. Q1: What does exec {fd}<>file do in a Bash script? A1: The exec {fd}<>file command is used to open a file for both reading and writing. {fd} automatically assigns a file descriptor to the file named file. This means that the file is attached to a newly allocated file descriptor (other than 0, 1, or 2, which are reserved for stdin, stdout, and stderr, respectively).

In Linux shell scripting, managing inputs and outputs efficiently can greatly enhance the functionality and flexibility of your scripts. One interesting feature of Bash is file descriptor manipulation, particularly using exec to manage and redirect output streams. Today, we will explore how to use exec 3>&1 to redirect a subshell's output to a parent's file descriptor (fd). Q&A on Using exec 3>&1 Q1: What is exec in the context of Bash? A1: exec is a built-in Bash command used to execute commands in the current shell environment without creating a new process. When used with redirection, it affects the file descriptors in the current shell.