Скачать или смотреть How to Use Bash Script Functions to Save Output to a File

Learn how to create a `Bash script` function that saves command outputs to files efficiently. This guide walks you through step-by-step instructions including examples.
---
This video is based on the question https://stackoverflow.com/q/62429376/ asked by the user 'Rookie' ( https://stackoverflow.com/u/8751181/ ) and on the answer https://stackoverflow.com/a/62429562/ provided by the user 'chepner' ( https://stackoverflow.com/u/1126841/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Bash script - function to save output to a file

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Use Bash Script Functions to Save Output to a File

Are you looking to save the output of commands and functions in your Bash scripts to separate files? If yes, you’ve come to the right place! This guide will help you create a Bash function that captures and saves outputs efficiently. Let’s dive in!

The Problem

When working with Bash scripts, especially for system information gathering, it's common to want the outputs saved to specific files. For example, imagine you have a function that retrieves kernel information:

[[See Video to Reveal this Text or Code Snippet]]

The goal is to save this output into a file named correspondingly while allowing you to create other functions for different types of information, like hostname or system memory.

The Solution: Using tee to Capture Output

Understanding the tee Command

To capture your command outputs and simultaneously save them to a file, we can use the tee command. Its primary function is to read from standard input and write to standard output and files. The versatility of this command allows you to easily write output to files and view it in the terminal at the same time.

Basic Function with tee

Here’s how you can define a kernel_info function to write output to a file using tee:

[[See Video to Reveal this Text or Code Snippet]]

In this code:

The curly braces {} are used to group commands.

printf constructs the output string "Kernel version: ".

uname -v provides the actual version of the kernel you are running.

The -a option tells tee to append to the specified file rather than overwrite it.

Parameterizing the Function

To make the function more flexible, you can allow it to accept a filename as a parameter. This way, you can define different output files as needed:

[[See Video to Reveal this Text or Code Snippet]]

How It Works:

local fname: This declares a local variable for the filename.

fname=${1:-/default/path/to/kernel_info}: This line assigns the first argument passed to the function as the filename, with a default path as a fallback if no argument is given.

Example Usage

Now, you can call the function like this:

[[See Video to Reveal this Text or Code Snippet]]

This gives you the flexibility you need to save outputs to different locations while keeping your code organized.

Conclusion

Using the tee command in a function allows Bash users to seamlessly capture and save outputs without complicating the process. Now you are equipped to enhance your Bash scripts by saving command outputs efficiently!

Happy scripting! If you have any further questions, feel free to ask!