BatchRenamer.java

import java.io.*;

public class BatchRename {

	private static File userfile;

	private static void renameAll(File folder) throws Exception{

		String currentname;
		String newname;
		File newfile;

		for (File fileEntry : folder.listFiles()) {

			// Recursively go through directories
			if (fileEntry.isDirectory()) {
				renameAll(fileEntry);
			}
			else {
				currentname = fileEntry.getName();
				newname = currentname.replaceAll(" ", "-");

				// Check to see if file needs to be renamed
				if (!(newname.equals(currentname))) {
					newfile = new File(newname);

					// Report progress
					if (fileEntry.renameTo(newfile)) {
						System.out.println("Rename of " + fileEntry.getName() + " successful");
					}
					else {
						System.out.println("Error renaming " + fileEntry.getName() + " " + newname + "");
					}
				}
			}
		}
	}

	public static void main(String[] args) throws Exception{

		String userfile_str;

		if (args.length == 1) {

			userfile_str = args[0];
			userfile = new File(userfile_str);
			renameAll(userfile);
		}
		else {
			System.out.println("Usage: java BatchRename <directory path>");
		}
	}
}