Bash Script to Shorten File Names Recursively

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In the world of file management, maintaining organization and efficiency is crucial. Long file names can lead to confusion and clutter, especially when dealing with numerous files across multiple directories. This article will walk you through creating a Bash script that recursively shortens file names in a specified directory while preserving the original file extensions. The script will respect the length of the file names based on a character limit specified as a command-line argument.

Prerequisites

  • A basic understanding of Bash scripting.
  • Familiarity with terminal commands and file navigation.
  • Knowledge of how to pass arguments to a script.
  • Ensure you have the rename utility installed (usually pre-installed in most Linux distributions).

DID YOU KNOW?

Shortening file names not only helps with organization but also reduces the risk of errors when typing file paths in commands.

The Script

This script will traverse the specified directory and its subdirectories, shortening the file names according to the character limit provided while retaining the file extensions. This ensures that files that are already shorter than or equal to the specified character limit remain unchanged.

#!/bin/bash

if [ $# -ne 2 ]; then
    echo "Usage: $0  "
    exit 1
fi

directory=$1
max_length=$2

find "$directory" -type f | while read -r filepath; do
    dir=$(dirname "$filepath")
    filename=$(basename "$filepath")
    extension="${filename##*.}"
    nameWithoutExt="${filename%.*}"
    
    if [ ${#nameWithoutExt} -gt $max_length ]; then
        newname=$(echo "${nameWithoutExt: -$max_length}.$extension")
        mv "$filepath" "$dir/$newname"
    fi
done

Step-by-Step Explanation

NOTE!

This script operates on all files within the directory and subdirectories. Make sure to use it in a directory where the files can be altered safely.

Let’s break down the script step-by-step.

  1. Input Validation: The script checks if the correct number of arguments is provided; that is, the directory to process and the maximum filename length.
  2. Directory Traversal: Using the find command, it locates all files in the specified directory and its subdirectories.
  3. File Name Processing: For each file found, the script extracts the directory, file name, and its extension. It then determines if the length of the name (excluding the extension) exceeds the specified limit.
  4. Renaming Logic: If the file name exceeds the length, it constructs a new name using the last characters based on the limit provided, retains the extension, and executes the rename operation.

How to Run the Script

To successfully execute the script, follow these steps:

  1. Open your terminal and navigate to the directory where the script is saved.
  2. Make the script executable by running chmod +x shorten_filenames.sh.
  3. Run the script with the command: ./shorten_filenames.sh /path/to/directory max_length, replacing /path/to/directory with your target directory and max_length with your desired character limit.

Conclusion

This Bash script is a powerful tool for managing file names efficiently. By customizing your file names while preserving extensions, you can maintain simplicity and clarity in your file system. Whether you manage a large volume of documents or just want to tidy up your directories, this script provides a systematic solution.

FAQ

  1. What happens if I provide a directory that doesn’t exist?

    The script will display an error message stating that the directory cannot be found and will exit without making any changes.

  2. Can I specify a length longer than the names of some files?

    Yes, if you specify a maximum length longer than the existing file names (excluding extensions), those files will remain intact.

  3. Will this script affect directories?

    No, this script only targets files. Directories will not be renamed.

  4. Is it possible to revert the changes made by this script?

    No, once the files are renamed, the original names are lost unless you have a backup or a reference of the original names.

Troubleshooting

If you encounter issues while running the script, consider the following:

  • Permission Denied: Ensure you have the necessary permissions to rename files within the directory.
  • Command Not Found: Ensure that the script’s path is correctly specified, and that the script is executable.
  • No files found: Make sure the directory you specified contains files; if it is empty, the script will not perform any action.

 

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