Скачать или смотреть Creating a Bash Script to Search for User Input in a File

Learn how to build a `Bash` script that efficiently searches user-inputted names in a file and returns a single output for matches or no matches.
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This video is based on the question https://stackoverflow.com/q/71570791/ asked by the user 'arthur' ( https://stackoverflow.com/u/18541232/ ) and on the answer https://stackoverflow.com/a/71571927/ provided by the user 'Juranir Santos' ( https://stackoverflow.com/u/10424004/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Creating a Bash Script to Search for User Input in a File

When learning Bash scripting, one common exercise is building scripts that can parse and search through text files. If you've ever needed to fetch records from a file containing user data in a specific format, this post is for you!

Understanding the Problem

Imagine you have a file that contains names, phone numbers, and emails formatted like this:

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

You want to create a script that allows users to input a name and retrieves the corresponding record if it exists. However, if you are not careful with your script, it could produce multiple outputs - showing "person found" for every matching entry, as well as "couldn't find anyone" for each non-match. This can be frustrating as it clutters the output and is not user-friendly.

The Solution

To resolve the issue of repetitive outputs and provide a streamlined response, we can utilize a combination of string manipulation and conditionals in Bash. Below is a structured approach to achieve the desired outcome.

Revised Code

Here’s the corrected version of the script you can implement:

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

Breaking Down the Code

Reading Names:

We use awk -F'[:]' to split the content of the file by colons, grabbing only the name part.

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

Setting Internal Field Separator (IFS):

By setting IFS=$'\n', we ensure that each name is treated as a separate line, allowing us to loop through them easily.

Input Name:

The script accepts user input as the name variable. This will be the name searched within the file.

Searching for the Name:

We loop through each name, checking if it matches the user’s input.

If a match is found, we utilize grep to find the line number of the match, echoing that information to the user.

Avoiding Multiple Outputs:

With the introduction of a found flag, we can control the output:

If a match occurs, we set found=1 and break out of the loop.

After all checks, if found remains 0, we know that no matches were found, allowing for a single, clear output.

Conclusion

By employing this revised script, you can now search user inputs in a file without cluttering the output with multiple matches or irrelevant messages. This not only enhances user experience but also improves the efficiency of your Bash scripts.

Now, it's time to put this knowledge to practice! Create your own dataset and modify the script as needed to become proficient in Bash scripting.

Happy scripting!