The Linux Page

Help other users realize that everything is possible, especially avoiding Windows for their own personal use.

Welcome to The Linux Page


Fox Trot by Bill Amend. Click to enlarge.
Click to enlarge

This site is a collection of my own work with Linux. Certain things are easy, others take time to decipher and if I ever need to repeat the work (which usually happens!), then I need to remember everything by memory or... have a site with all the steps taken and to take again.

The following are my most recent posts:

A message in a bottle, you might as well not ever bother...

Today I learned that by default Ubuntu doesn't install an MTA.

I've been installing Postfix on my computers and never noticed that because it's like part of the things I install even before I start doing anything on my computer.

However, a default basic Ubuntu install comes bare and does not offer a sendmail tool.

Looking at a certain number of computers, I noticed that the /var/mail folder was empty. That in itself wasn't really anything to worry about, but I was still wondering, how come?! I run CRON on those 13 computers and it never fails??? Oh yeah because on my ...

The Ubuntu Logo using a wood texture

(Picture above represents the logo of Ubuntu, a Linux distribution.)

The following is a list of the Ubuntu Releases with their versions and their name.

I find it really annoying when someone says "I have such" and he/she has no clue what version (i.e. 7.10) it is. Then I have to look it up because I don't memorize the numbers to the names, but I know what the numbers entitles.

So... I need a table and I had one on Wikipedia, but that was wiped out. So now, I'll keep my own here and I'll try to keep it up to date. I start with the version Mar 16, 2009 from the Ubuntu ...

An opened laptop optical drive with a literally burned CD disk showing.

Create ISO File to Burn

When creating a CD you use mkisofs (make ISO file system--ISO stands for International Standard Organization, a non-profit organization used to write standard procedures used in business and other places to better organize interoperability between many companies in the world.)

mkisofs -o my-cd.iso directory

The "directory" are all the files you want to write to the ISO file.

Verify Disk Before Burning

Then you should verify that it looks as you expected. This is done by mounting the ISO file:

sudo mount -o loop my-cd.iso /mnt/cd

Assuming ...

Virtual Mount of Rocks with a Beautiful Sunset in the Background

Ordeal

Today I made a mistake and create the file /etc/sudoers.d/timeout which was definitely not compatible with sudo. The file was JSON when sudo only accepts very basic var=value lines.

Result?

I could not use sudo anymore on that VM. I had to find a way to fix the file system without having to rebuild the entire disk because that would have taken way too long.

How to Mount a VDI File

Since your VDI (VirtualBox Disk Image) files are literally disk files, they should be mountable, right? Yes! They are. Actually, that's certainly exactly what the VirtualBox code does, but ...

A treasure chest full of coins, jewels, and ornaments.

As I am now using git, I like to create my own repositories. In most cases the documentation is not that easy to follow. Here are the instructions I use.

First of all, I setup my own personal configuration (it can be used as a global setup for you). This is written in the ~/.getconfig and looks like this:

[user]
    name = AlexisWilke
    email = me@my-top-secret-email-address.com

[core]
    excludesfile = ~/.gitignore
[push]
    default = simple
[giggle]
    main-window-maximized = false
    main-window-geometry = 1114x789+144+184
    file-view-vpane-position = 389
    ...

A 1U server, what a servlet (called at Droplet at DigitalOcean) or VPS represents although you have many within a single computer now.

Introduction

When I create a new DigitalOcean droplet I have to run a few commands that I don't otherwise use very much at all so I was thinking that adding them here would make it easier to remember.

Creating a New Key with ssh-keygen

I use the same key for each group of computers I manage there. Each time I create a new group, I create a new key with the ssh-keygen command as so:

% ssh-keygen -t rsa
...
Enter file in which to save the key (/home/alexis/.ssh/id_rsa): ...
...

WARNING: as we can see ssh-keygen asks you to write the resulting keys using the default ...

Stylish Motorbike Speedometer

Situation

I had some problems (and may still have some problems) with a computer which at times drops its transfer speed to 100Mb instead of running at full speed (1Gb).

I think that one possible problem is that the card detects a "weak" cable, probably because it's a very long one.

Today I was surprised that it ran at full speed, though. I really thought that the network card was dead for good, especially because I tested with a MS-Windows laptop which would get the 1Gb transfer rate as expected.

Linux

Discovering Connections

Under Linux, you first need to ...

A bunch of icicles with droplets at the bottom as they are slowly melting.

In an Excel Spreadsheet (Microsoft)

I have been wondering how to lock a few rows and/or columns at the top-left in Excel. I have seen that being done many times, but did not know how to do it myself...

In the Windows menu (Before Office 2007) and in the View menu (Since Office 2007) you will find an option named Freeze Panes. You have three selections:

  1. Freeze the selected top rows
  2. Freeze the selected left columns
  3. Freeze the selected top rows and left columns

If you just need one row and/or column, place your cursor in the A1 cell (the very first top-left cell).

...

A couple of seahorses mating

Problem Loading SeaMonkey

Today, I finally upgraded to SeaMonkey 2.49.3.

It was out on Nov 4, 2017 but I did not check for it any time sooner. Bad for me as there were some bugs in 2.48 that banks and such were warning about (oh and WordPress too...)

Anyway. I downloaded the new version. Extracted the files. Updated my icon with the new path. Click on the icon to open the browser. Nothing.

So I know that it is likely that it prints out some errors when nothing happens like that, so I went to my console and tried to start seamonkey in my command line window.

Indeed, errors were ...

Bluish smoke like design representing a modern library

Introduction

The Qt library version can be retrieved in all sorts of ways, using your command line or C++ code. There are a few I use:

Test Whether Qt is Installed

Before testing the version, you probably want to verify that Qt is installed.

qmake is pretty much always installed whenever you install Qt. The qt5-default package directly depends on qtchooser which includes qmake. Therefore, under a Linux system we can simply use the following script to determine whether Qt is installed:

if ! test -x /usr/bin/qmake
then
  # The Qt library is missing...
  echo "error: This ...

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