title: java regular expression in a file content
body: <p>How to use regular expressions in a file content. i am having group of files, i want to search a string in all the files and replace in all the files.</p>
  
  <p>can anybody help me in this? the cose is below:</p>
  
  <pre><code>package com.java.far;
  import java.io.*;
  import java.util.regex.Matcher;
  import java.util.regex.Pattern;
  public class ReplaceAll {
  
      public static void main(String[] args)throws IOException {
  
          Runtime r=Runtime.getRuntime();
          System.out.println(r.freeMemory());
  
          String path="D:\\JOBRELATED\\FAR";
          String files;
          File folder=new File(path);
          File[] listofFiles=folder.listFiles();
          for (int i = 0; i &lt; listofFiles.length; i++) {
              if (listofFiles[i].isFile()) {
                  files=listofFiles[i].getName();
                  if(files.endsWith("tex")){
                  System.out.println(files);
  
                  BufferedReader br=new BufferedReader(new FileReader("D:\\JOBRELATED\\FAR\\"+files));
                  String line;
                  while((line=br.readLine())!=null){
                  Pattern p=Pattern.compile("Diamond in History and Research");
                  Matcher m=p.matcher(line);
                  int count=0;
                  while (m.find()) {
                      count++;
                      //System.out.println(m.start() +"\t"+ count);
                      System.out.println(line);
                      m.replaceAll("abc");
  
  
                  }
                  }
  
              }
              }
          }
  
  
      }
  }
  </code></pre>