if ((args.length == 0) || (args.length > 2)) {
System.out.println("Usage: java Grep <substring> [<filename>]");
System.exit(0);
}
try {
DataInputStream d;
if (args.length == 2)
d = new DataInputStream(new FileInputStream(args[1]));
else
d = new DataInputStream(System.in);
GrepInputStream g = new GrepInputStream(d, args[0]);
String line;
for(;;) {
line = g.readLine();
if (line == null) break;
System.out.println(line);
}
g.close();
}
catch (IOException e) { System.err.println(e); }
