Question

So I’m using the terminal and I issue the command

clear | java email11

And I get this crazy execution of half the code I wrote

“Enter input filename [default: fileContainingEmails.txt]: Enter
output filename [default: ]:”

then an error:

Enter input filename [default: fileContainingEmails.txt]: Enter output filename [default: 
]: Exception in thread "main" java.util.NoSuchElementException: No line found
    at java.util.Scanner.nextLine(Scanner.java:1516)
    at email11.main(email11.java:39)

all together like:

myMachine:mydir me$ clear | java email11
Enter input filename [default: fileContainingEmails.txt]: Enter output filename [default: 
]: Exception in thread "main" java.util.NoSuchElementException: No line found
    at java.util.Scanner.nextLine(Scanner.java:1516)
    at email11.main(email11.java:39)

and the termainal goes back to:

myMachine:mydir me$ 

So my question is, how do I pipe this command successfully?

Answer 1

Try

$ clear | xxd

which gives you something like

0000000: 1b5b 481b 5b32 4a                        .[H.[2J

This is the input to your email11 program. Probably not your intention.
Just do:

$ clear; java email11

That simply runs the two commands, one after the other, as if you had typed them on two separate lines.

You should probably read the documentation for the command shell you’re using. The default shell on OSX is bash; you can see the manual here.