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Jiew Meng's questions

Martin Hope
Jiew Meng
Asked: 2012-02-15 16:13:27 +0800 CST
  • 21

I am reading Debian vs. Ubuntu vs. Linux Mint: Which Distribution Should You Use?

Ubuntu, on the other hand, is made to include a good combination of new and stable ... Some packages can be used on both distributions, while others are specifically for one or the other

If Ubuntu is based on Debian, how is it more updated? Does it simply use different apt soures?

Again since it's based on Debian, why are there differences in package compatibility? Does it simply have some different things installed?

Can I say:

  • All Debian packages will work on Ubuntu.
  • All Ubuntu packages will work on Linux Mint (based on Ubuntu).
package-management debian compatibility
Martin Hope
Jiew Meng
Asked: 2011-10-05 04:03:47 +0800 CST
  • 10

I have installed JUnit on my Ubuntu 11.04

sudo apt-get install junit

Then created a test file like: 

import org.junit.*;

public class TestBasicLinkedList {
  @Test public void testCanAdd(String[] args) {
    BasicLinkedList<Integer> list = new BasicLinkedList();
    list.add(new BasicListNode<Integer>(1));
    assertTrue(list.size() == 1);
    assertTrue(list.getFirst().getElement().equals(1));
  }
}

Then tried running in terminal 

java org.junit.runner.JUnitCore TestBasicLinkedList.java

Got: 

Exception in thread "main" java.lang.NoClassDefFoundError: org/junit/runner/JUnitCore
Caused by: java.lang.ClassNotFoundException: org.junit.runner.JUnitCore
    at java.net.URLClassLoader$1.run(URLClassLoader.java:217)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:205)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:321)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:294)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:266)
Could not find the main class: org.junit.runner.JUnitCore. Program will exit.

How do I use JUnit? Is there a better shorter way of using it than the long command java org.junit.runner.JUnitCore TestBasicLinkedList.java? Perhaps something like junit *.Tests.java maybe?

java
Martin Hope
Jiew Meng
Asked: 2011-08-25 17:18:29 +0800 CST
  • 113

One of the ways I quickly rename files in Windows is 

F2 > Rename > Tab (to next file) > Rename ...

But in Ubuntu/Nautilus, I can't tab to next file. But being on Linux, I think there must be a command line alternative.

However, sometimes, I may want more control over how to rename specific files. In that case, perhaps its better to be able to tab to the next file

command-line
Martin Hope
Jiew Meng
Asked: 2011-08-14 05:10:37 +0800 CST
  • 7

I am under the impression that if I include the line

#!/bin/bash

at the start of my file, it will be recognized as a bash script that I can run just by 

file.sh

instead of 

sh file.sh

But in my case, file.sh gives something like test.sh gives test.sh: command not found. Why is that?

UPDATE

I notice I need to use ./. But I thought it will look in the current directory anyway?

./test.sh
bash
Martin Hope
Jiew Meng
Asked: 2011-08-14 05:07:09 +0800 CST
  • 25

I want to test if there is any output from the diff (test if files are same), if none echo "Passed $x" else echo "Failed $x". I came up with some intermidiate step (save the output from diff to a file then read from file)

diff "./helloworld$x.out" "./output/helloworld$x.out" > tmp.txt;
output="`cat tmp.txt`";

if [ "$output" = "" ];
  then
    echo "Passed $x";
  else
    echo "Failed $x";
  fi;

I'm sure the code can be improved? Main question is: is it possible to save the output from diff directly into a variable?

bash
Martin Hope
Jiew Meng
Asked: 2011-05-22 22:04:56 +0800 CST
  • 11

GPG error: http://extras.ubuntu.com natty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 16126D3A3E5C1192

I think I selected to install things from extras.ubuntu.com when I used the expert mode installer, but I got the above error when doing apt-get update. How do I fix this?

apt
Martin Hope
Jiew Meng
Asked: 2011-05-11 06:38:03 +0800 CST
  • 20

I am looking for a way to log & monitor my server hardware temperatures and load (like for CPU or RAM). How might I do that?

Objective is to:

  • ensure hardware is not heating up
  • identify what should be upgraded & what is in excess (like perhaps to learn maybe not to get such a good CPU for example)

Ok I can use one of the applets that live in the task bar but what about logging?

hardware