#!/bin/bash

# Check if the required arguments are provided
if [ "$#" -ne 3 ]; then
    echo "Usage: $0 <directory> <search_expression> <replace_expression>"
    exit 1
fi

# Assign arguments to variables
directory="$1"
search_expr="$2"
replace_expr="$3"

# Check if the directory exists
if [ ! -d "$directory" ]; then
    echo "Error: Directory '$directory' does not exist."
    exit 1
fi

# Function to rename files
rename_files() {
    local dir="$1"

    # Loop through all files and directories in the current directory
    for item in "$dir"/*; do
        if [ -d "$item" ]; then
            # If it's a directory, recurse into it
            rename_files "$item"
        elif [ -f "$item" ]; then
            # If it's a file, rename it if it matches the search expression
            local filename=$(basename "$item")
            if [[ "$filename" == *"$search_expr"* ]]; then
                local new_filename="${filename//$search_expr/$replace_expr}"
                local new_path="${item%/*}/$new_filename"
                mv "$item" "$new_path"
                echo "Renamed: $item -> $new_path"
            fi
        fi
    done
}

# Start the renaming process
echo "Starting renaming process in directory: $directory"
rename_files "$directory"
echo "Renaming process complete."