How to get current user name of Linux in Java

Question

I have a Selenium tests written in Java which runs as Jenkins job. I need to have chmod set up to 777 cause otherwise it throws me an error. But I would like to set up chmod properly to somenthing like 775. The problem is that I dont know who is the user which runs the Java tests. I have this code in Java

System.out.println(Runtime.getRuntime().exec("whoami"));

which returns this: Process[pid=2116487, exitValue=0] Can somebody tell me please what is it? Obviously it is not a user I can set up as owner or as a group of the repository.

Thanks.

Does this answer your question? [Get login username in java](https://stackoverflow.com/questions/797549/get-login-username-in-java) — Thomas, Jun 22 '21 at 08:18
https://stackoverflow.com/questions/473446/java-current-machine-name-and-logged-in-user check this — YaDav MaNish, Jun 22 '21 at 10:48

score 2 · Accepted Answer · answered Jun 22 '21 at 09:50

To get the output of the process, you need to attach the InputStream of to the normal output of the subprocess. Then, you can read from it by creating a BufferedReader. To get the first line of the output of the process (on stdout) you can use this code:

Process proc = Runtime.getRuntime().exec("whoami");
BufferedReader stdin = new BufferedReader(new InputStreamReader(proc.getInputStream()));
String username = stdin.readLine();
System.out.println(username);

You can also get the InputStream of the error output of the subprocess (stderr) with proc.getErrorStream() if this should be necessary.

However, there is a better way if you want to get the username of the user executing the VM:

String username = System.getProperty("user.name");
System.out.println(username);

Mathias · Answer 2 · 2021-06-22T10:22:11.397

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You are not getting the output of the process "whoami", but the process properties. Try

System.out.println(new Printstream(Runtime.getRuntime().exec("whoami").getOutputStream()));

edited Jun 22 '21 at 10:22

answered Jun 22 '21 at 08:16

Mathias

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What namespace is Printstream? – Čamo Jun 22 '21 at 08:31
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java.io.PrintStream – Mathias Jun 22 '21 at 08:36
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BTW, my IDE (Eclipse) already proposed this namespace. And it showed the Javadoc for the command `exec`, which shows that the return of the function is the process properties. Your problem could have been avoided by using an IDE. – Mathias Jun 22 '21 at 08:38
It was something between the PC and the chair. I have InteliJ IDEA for it. I saw more than one packege for Pritstream. Now it is only one. Unbelievable... – Čamo Jun 22 '21 at 08:42
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Sometimes a little break or sleep resolves all problems... ;) – Mathias Jun 22 '21 at 08:45
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Ok but this command does not write to the console output. – Čamo Jun 22 '21 at 09:26
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Thanks, I had a typo in the code (the best place for typos...) – Mathias Jun 22 '21 at 10:22

score 0 · Answer 3 · answered Jun 22 '21 at 10:23

0

Do you want this?

System.getProperty("user.name")

answered Jun 22 '21 at 10:23

James Mudd

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How to get current user name of Linux in Java

3 Answers3