Passing a file argument in Java

Question

I am wondering how to pass a file as an argument on linux command line .

public class Main {
    public static void main(String[] args){
        System.out.println(args[0]);
    }
}

For the above code if I do:

java -jar myJava.jar blah.txt

It prints blah.txt to the screen.

But I have a sample line of code that looks like this:

java -jar myJava.jar < blah.txt

How am I able to get the value of blah.txt from the above command?

Answer 1

Use one of the techniques for reading from System.in where the file is being redirected such as Scanner

Scanner scanner = new Scanner(System.in);
while (scanner.hasNextLine()) {
    String line = scanner.nextLine();
    ...
 }

Answer 2

try the following

java -jar myJava.jar 'blah.txt'

The quotes indicate that the argument is literal.

double quotes will also work, but will not prevent things like variable expansion, so single quotes is better when trying to pass a literal string.