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How to record multiple applications and microphone into one audio file on Linux

Step 0. Terminology

Sinks are for output, sources are for input. To stream source to sink a loopback must be created. More shall you find there.

Step 1. Create output sink that will be recorded

Our output sink will be named recording.

pacmd load-module module-null-sink sink_name=recording sink_properties=device.description=recording

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Ramp up your Kubernetes development, CI-tooling or testing workflow by running multiple Kubernetes clusters on Ubuntu Linux with KVM and minikube.

In this tutorial we will combine the popular minikube tool with Linux's Kernel-based Virtual Machine (KVM) support. It is a great way to re-purpose an old machine that you found on eBay or have gathering gust under your desk. An Intel NUC would also make a great host for this tutorial if you want to buy some new hardware. Another popular angle is to use a bare metal host in the cloud and I've provided some details on that below.

We'll set up all the tooling so that you can build one or many single-node Kubernetes clusters and then deploy applications to them such as OpenFaaS using familiar tooling like helm. I'll then show you how to access the Kubernetes clusters from a remote machine such as your laptop.

Pre-reqs

• This tutorial uses Ubuntu 16.04 as a base installation, but other distributions are supported by KVM. You'll need to find out how to install

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  # Create new from old
  git tag new old

  # Remove old tag
  git tag -d old

  # Sync changes from old tag to remote
  git push origin :refs/tags/old

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# EditorConfig helps developers define and maintain consistent
# coding styles between different editors and IDEs
# editorconfig.org

root = true

[*]
charset = utf-8
end_of_line = lf
insert_final_newline = true

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Converting mkv to mp4 with ffmpeg

Essentially just copy the existing video and audio stream as is into a new container, no funny business!

The easiest way to "convert" MKV to MP4, is to copy the existing video and audio streams and place them into a new container. This avoids any encoding task and hence no quality will be lost, it is also a fairly quick process and requires very little CPU power. The main factor is disk read/write speed.

With ffmpeg this can be achieved with -c copy. Older examples may use -vcodec copy -acodec copy which does the same thing.

These examples assume ffmpeg is in your PATH. If not just substitute with the full path to your ffmpeg binary.

Single file conversion example

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## Generate a new SSH key

Follow this command, ensure that you change your-identifier with your own, it could be an unique name or email address (recommended)

```
$ ssh-keygen -t rsa -b 4096 -C "your-identifier"
```

An output from those command look like below.
If asked, simply press enter to follow the suggested value (/home/yours/.ssh/id_rsa)

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# non root user example for alpine
#
# usage:
# $ docker build --build-arg "USER=someuser" --tag test .
# $ docker run --rm test

FROM alpine

ARG USER=default
ENV HOME /home/$USER

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Moved to git repository: https://github.com/denji/nginx-tuning

NGINX Tuning For Best Performance

For this configuration you can use web server you like, i decided, because i work mostly with it to use nginx.

Generally, properly configured nginx can handle up to 400K to 500K requests per second (clustered), most what i saw is 50K to 80K (non-clustered) requests per second and 30% CPU load, course, this was 2 x Intel Xeon with HyperThreading enabled, but it can work without problem on slower machines.

You must understand that this config is used in testing environment and not in production so you will need to find a way to implement most of those features best possible for your servers.

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cfg.parser () {
    fixed_file=$(cat $1 | sed 's/ = /=/g')  # fix ' = ' to be '='
    IFS=$'\n' && ini=( $fixed_file )              # convert to line-array
    ini=( ${ini[*]//;*/} )                   # remove comments
    ini=( ${ini[*]/#[/\}$'\n'cfg.section.} ) # set section prefix
    ini=( ${ini[*]/%]/ \(} )                 # convert text2function (1)
    ini=( ${ini[*]/=/=\( } )                 # convert item to array
    ini=( ${ini[*]/%/ \)} )                  # close array parenthesis
    ini=( ${ini[*]/%\( \)/\(\) \{} )         # convert text2function (2)
    ini=( ${ini[*]/%\} \)/\}} )              # remove extra parenthesis

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#!/usr/bin/env ruby
# Usage: gitio URL [CODE]
#
# Turns a github.com URL
#  into a git.io URL
#
# Copies the git.io URL to your clipboard.

url  = ARGV[0]
code = ARGV[1]