HashReplace.java

import java.io.*;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Matcher;

import org.apache.commons.io.FileUtils;

import static java.lang.System.exit;

public class HashReplace {

    public static void main(String[] args) {
        //args[0] hashes (format hash:plaintext)
        //args[1...] file(s) to replace in
        if(args.length < 2) {
            System.err.println("not enough parameters");
            exit(1);
        }

        File   hashes    = new File(args[0]);
        File[] textFiles = new File[args.length-1];

        for (int i = 0; i<args.length; i++) {
            File f = new File(args[i]);
            if (!f.exists()) {
                System.err.println("file " + args[i] + " does not exist");
                System.exit(1);
            }
            if (i > 0) {
                textFiles[i-1] = f;
            }
        }

        HashMap<String,String> hashMap = new HashMap<>();
        try {
            BufferedReader in = new BufferedReader(new InputStreamReader(new FileInputStream(hashes.toString()), "UTF-8"));
            String s;
            while ((s = in.readLine()) != null) {
                String hash = s.substring(0, s.indexOf(":")).toLowerCase();
                String plaintext = s.substring(s.indexOf(":")+1);
                System.out.println("reading " + hash + " <-> " + plaintext);
                hashMap.put(hash, plaintext);
            }
        } catch (UnsupportedEncodingException e) {
            //won't happen
        } catch (IOException e) {
            //shouldn't happen
        }

        for (File f : textFiles) {
            System.out.println("replacing in file " + f.toString());
            try {
                String content = FileUtils.readFileToString(f, "UTF-8");
                for (Map.Entry<String,String> entry : hashMap.entrySet()) {
                    content = content.replaceAll("(?i)" + Matcher.quoteReplacement(entry.getKey()), Matcher.quoteReplacement(entry.getValue()));
                }
                FileUtils.writeStringToFile(f, content, "UTF-8");
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        System.out.println("finished");
    }
}