How to write into and read from command line in Java ?

Question

Possible Duplicate:
Java external program

I am trying to wrtie a program to write a command on a command line,

for example;

ipconfig

and then get the response of the command so I want to both write command to a command line and get its response. I have searched about it on the net and saw that apache cli is used to do this in Java but actually I did not clearly get how it can be done. Can you please help me about my situation with a few line of codes or tutorials about both writing and reading commands please?

Thank you all very much

The [apache cli package](http://commons.apache.org/cli/) helps you process the command line parameters which were given to your program when it was invoked. AFAIK, it doesn't do anything with invoking external commands or capturing input from them. — GreenMatt, Sep 15 '11 at 15:21
@Chris, just like I answered it myself. Though I try and not give actual code and leave something for the asker to do in such simple cases :) — Miserable Variable, Sep 15 '11 at 15:22

score 8 · Accepted Answer · edited Jun 20 '20 at 09:12

8

You could start it as a Process and capture the InputStream of the process as described here:

Runtime runtime = Runtime.getRuntime();
Process process = runtime.exec("ipconfig"); // you might need the full path
InputStream is = process.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String line;

while ((line = br.readLine()) != null) {
    System.out.println(line);
}

Edit: I copied this code from above link, but the code seems wrong. Don't you need the output stream for this? Edit2: no.

getInputStream()

Gets the input stream of the subprocess. The stream obtains data piped from the standard output stream of the process represented by this Process object.

Nice naming convention...

edited Jun 20 '20 at 09:12

Community

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answered Sep 15 '11 at 15:08

CodeCaster

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but it works. I tried it and can get the result of the query . I will try to do it with also Process.getOutputStream() – mehmetozer Sep 15 '11 at 15:39
My bad. I am going delete my previous comment. – Miserable Variable Sep 15 '11 at 15:51

score 0 · Answer 2 · answered Sep 15 '11 at 15:06

0

See Process and ProcessBuilder classes.

Specifically, you would create a Process. Process.getOutputStream() gives an InputStream, from which you read what the process's output. You also need to read Process.getErrorStream() for any errors that the process reports.

answered Sep 15 '11 at 15:06

Miserable Variable

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Thanks a lot, and where I can have basic tutorials about the command lines and examples ? Do you know a good site for that ? – mehmetozer Sep 15 '11 at 15:14

score 0 · Answer 3 · answered Sep 15 '11 at 15:25

0

Try this for inputting the user value.

java.util.Scanner input = new Scanner( System.in);

System.out.println("Please Enter your Name: ");             
    String empName = input.nextLine();

answered Sep 15 '11 at 15:25

Jayy

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Please reread the question. He does not wanted to read the stdin, he wants to read the output of a spawned process. – Miserable Variable Sep 15 '11 at 15:31

How to write into and read from command line in Java ?

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