If when trying to start a vm, for example using vagrant, you get the error message that the host network adapter cannot be created:

There was an error while executing `VBoxManage`, a CLI used by Vagrant
for controlling VirtualBox. The command and stderr is shown below.

Command: ["hostonlyif", "create"]

Stderr: 0%...
Progress state: NS_ERROR_FAILURE
VBoxManage: error: Failed to create the host-only adapter
VBoxManage: error: VBoxNetAdpCtl: Error while adding new interface: failed to open /dev/vboxnetctl: No such file or directory
VBoxManage: error: Details: code NS_ERROR_FAILURE (0x80004005), component HostNetworkInterfaceWrap, interface IHostNetworkInterface
VBoxManage: error: Context: "RTEXITCODE handleCreate(HandlerArg*)" at line 94 of file VBoxManageHostonly.cpp

Make sure to first start the virtualbox GUI application. It does some extra checks, and sometimes highlights the permission problem:

In my case (OpenSuse 15.1 Leap), my user was not added to the vboxusers group. Via Yast > Users and Security .... and editing my user account it was a simple checkbox away. Remember to relog.

If that doesn't work, reloading the kernel extensions could help:

$ sudo dpkg-reconfigure virtualbox-dkms
$ sudo dpkg-reconfigure virtualbox
$ sudo modprobe vboxdrv 
$ sudo modprobe vboxnetadp

#opensuse #virtualbox #linux #vagrant

I was looking for a tea timer countdown but quickly realised I might as well use a countdown script for this. I based my script on the linked script but added a customizable notification at the end

$ nano ~/bin/countdown

#!/bin/bash
# v2 - 2019-05-01
secs=$1
msg=${2:-$1 seconds passed.}
while [ $secs -gt 0 ]; do
   echo -ne "$secs\033[0K\r"
   sleep 1
   : $((secs--))
done
notify-send 'Countdown Finished' "$msg"

$ chmod +x ~/bin/countdown
$ countdown 180 "Tea is ready."

#linux

On Linux operating systems, Spotify does not always show the file and view menus. This makes it harder to hide the "Find Friends" bar as there is no close button on the sidebar itself.

However there's another way: Click on the chevron in the top right corner next to your spotify username, then on Settings > Display Options > untick Show Friend Activity.

#linux #howto

After another hour of resolving issues with pyenv and a personal project that requires Python 3.7 I thought it best to note the steps I used to install Python 3.7.1 on OpenSUSE Tumbleweed:

# Install requirements for compiling Python
sudo zypper in zlib-devel bzip2 libbz2-devel libffi-devel libopenssl-devel readline-devel sqlite3 sqlite3-devel xz xz-devel 

# Compile Python
cd ~/Downloads
wget https://www.python.org/ftp/python/3.7.1/Python-3.7.1.tar.xz
tar xf Python-3.7.1.tar.xz
cd Python-3.7.1
./configure
make

# AltInstall ensures 3.7.1 is installed alongside your system python
sudo make altinstall

# Fix dynamic library loading
sudo ln -s /usr/local/lib64/python3.7/lib-dynload /usr/local/lib/python3.7/lib-dynload

I've updated the Common build problems · pyenv/pyenv Wiki page to reflect the updated required packages. Thanks to Andrew Cooke for the dynamic library fix

#python #linux

Linux is so userfriendly, so the rpm that can be downloaded is missing dependencies. However, I'm quickly becoming a fan of zypper and OpenSUSE's dependency handling, and comes to the rescue:

sudo zypper in cryptomator.rpm

Even though cryptomator made a mistake in signing part of the application, it can still be installed by pressing ignore. Are you sure you want to do that? It seems a bit crap for such an essential utility.

#linux

Both the official RPM and the discover package failed for me due to missing dependencies, without specifying what those are. However the following worked:

sudo zypper install dropbox-cli
dropbox start -i
dropbox autostart

#linux

Having wasted too much time installing Ubuntu on a laptop recently, I thought it would be helpful for the future self to document the issues.

Issues

sudo su
apt install cifs-utils
echo "//path/to/windows-share /mnt/team cifs credentials=/etc/samba/credentials,uid=1000 0 0" >> /etc/stab
cat > /etc/samba/credentials <<EOC
username=UserName
password=PassWord
EOC
chown root.root /etc/samba/credentials && chmod 400 /etc/samba/credentials

This document will get updated as I stumble and fix other issues.

App Alternatives

#linux

I've been finding that browsing has been slow for me lately on my linux box, which has Ubuntu 16.04 installed. After some investigation it seemed worthwhile to try to install a DNS cache to speed up DNS queries. This has sped up successive DNS queries from 21ms to 0ms, removing sluggishness.

sudo apt install bind9
cd /etc/resolvconf/resolv.conf.d
sudo echo "nameserver 127.0.0.1" >> head

Apply the configuration as follows:

sudo resolvconf -u

The improvement can be seen by using dig to query a domain and looking at the Query time output. After the first dig, subsequent digs return in 0 ms.

#linux

Ubuntu 17.10 comes with python3 3.6.3 installed by default but not pip and pipenv. We can install install pip systemwide and pipenv into the user local bin so we can use all the convenience when working with our python projects:

wget https://bootstrap.pypa.io/get-pip.py -O /tmp/get-pip.py
sudo python3 /tmp/get-pip.py
pip3 install --user pipenv
echo "PATH=$HOME/.local/bin:$PATH" >> ~/.profile
source ~/.profile

Sources: Installing Python 3 on Linux; pip installation; Installing pipenv; How to permanently set PATH on Linux

Update 9 Nov 2017: replaced curl with wget, thanks Peter

#python #technology

Today a problem came up where the files on my Samba fileshare did not indicate to my Windows system that they were changed. Software that relies on this information such as TortoiseHG and SimpleLESS would not know that the file had changed. This was especially obvious with SimpleLESS which should take the .less file and process it, but wouldn’t.

#link #linux

I recently set up a local development server running Ubuntu on VMware player. I thought it would be interesting to document the process and instructions so that it will be useful to others, and you can follow along / correct / improve this guide. On completion of this series you will end up with a complete LAMP local development system..

username: __________ password: __________ 

#linux

Once you understand Linux file permissions, the next step on the road to enlightenment is learning how to check the permissions for a file or directory.

via http://articles.slicehost.com/2010/7/17/checking-linux-file-permissions-with-ls&hl=en&strip=...">Slicehost Articles: Checking Linux file permissions with ls

#linux

Linux file permissions are strange and wondrous things. Start down the path of understanding by looking at the core concepts behind them before moving on to practical applications.

via Slicehost Articles: Linux file permission concepts

#linux

Today, after making a change to a php file, I had to update all copies of this file with the changes. The following command will update all files with the same name. Note that this will only work as expected if the name is unique. A theoretically better way to do it would be to find all files with a certain hash.

Anyways, here's the linux shell command. First copy the updated file into the current directory (/tmp for example):

find /target_path/ -iname "some_file.php" -exec cp new_file.php '{}' \;

#linux

After publishing the previous article about serve.sh - the shell script I created to easily serve websites in development - I made some changes to make it easier to run it from the terminal, for example over ssh. I thought I'd share it with you.

One of the problems with the original script was that it was optimized for a GUI setting - ie. start the script by clicking on it from the desktop. However usually I want to run it from the terminal. I don't like typing so I added code to make the script available from any directory to the ~/.bashrc:

export PATH=$PATH:~/bin

Then moved it to that path and renamed it to shave another 3 characters off the syntax:

mv ~/Desktop/serve.sh ~/bin/serve

In addition I noticed that prompting which site should be served was just a workaround for commandline arguments, which are now added. It doesn't check that you entered an argument though. So the new script now requires you to specify which directory you want to serve: to serve the current directory simply run:

serve .

Latest script contents:

#!/bin/bash
my_path=`readlink -f $1`
sudo rm /var/www
sudo ln -s $my_path /var/www
echo Now serving $my_path...

#development #linux

I am experimenting with using a Linux virtual machine as my web development environment of choice. I store the vm on a removable drive so that I can develop from any location, without having to setup a working environment. Previously I had to check out the repositories, setup a local webserver and I had trouble keeping things working, because every configuration change had to be applied in every location. Now it is all centralized and my life is simpler.

The aim is to make working on projects as easy as possible. I have all projects checked out in a folder called /var/sites. They are mostly PHP projects and because of my shared hosting environment they share a single apache configuration. How can I easily serve them? Having seperate virtualhosts for each project would result in me having to make manual changes on every location again, so this was not the way to go.

Instead I created a simple shell script that creates a symbolic link from the Apache's webroot to the project I am working on:

[gallery link="file"]

#!/bin/bash
echo "Available sites:"
ls  /var/sites

echo
echo -n "Type site to serve: "
read site
if [ -z "$site" ]
then
exit
fi

sudo rm /var/www
sudo ln -s /var/sites/$site /var/www

#development #linux

Our php.log was nearing 550MB so I was investigating how to rotate the logs. The easiest solution seems to be using logrotate (ubuntu linux) with a script like follows.

sudo nano /etc/logrotate.d/php5

/var/log/php5/*.log {

  #rotate daily
  daily

  #keep 14 days
  rotate 14

  missingok
  nocompress
  sharedscripts
  postrotate
  apache2ctl graceful
  endscript

}

You can check the configuration by running logrotate --force /etc/logrotate.d/php5

#php