convert m4a to mp3 in lunux via the command line

ex Lord Neckbeard at SuperUser

http://superuser.com/questions/704493/ffmpeg-convert-m4a-files-to-mp3-without-significant-loss-of-information-quali

$ mkdir mp3
$ for f in *.m4a; do ffmpeg -i "$f" -codec:v copy -codec:a libmp3lame -q:a 2 mp3/"${f%.m4a}.mp3"; done

getting set up with the raspberry pi 3 B and ubuntu linux

1. download the 16-04 for Pi3B image from the official Canonical page.

With the release of the Raspberry Pi 2 Model B and its ARMv7-based BCM2709 processor, it is now possible to run Ubuntu directly on the Raspberry Pi.

...

Raspberry Pi 3: ubuntu-16.04-preinstalled-server-armhf+raspi3.img.xz (4G image, 216M compressed)

...

This Raspberry Pi 3 image is built by Ryan Finnie using modified Xenial packages in a PPA (ppa:ubuntu-raspi2/ppa-rpi3), and is not supported directly by Canonical. 

2. initialize the SD card with the image

2.1 Decompress the archived image from within the Nautilus file explorer using the archive manager that comes pre-installed with 16-04.

2.2 uBuntu 16-04 comes pre-installed with a GUI disk-image tool 'Startup Disk Creator', which is as complicated to use as selecting the the image and the SD card.

3. login and configure

// at this point you will need to plug in a keyboard and monitor.

Login username is "ubuntu", password is "ubuntu". You will be asked to change the password on first login.

4. install the development platform

since we're going for a lite-weight install, and installing even the optimized xubuntu-desktop would require something like 1.6GB of space, so drop that idea, we're flying from the terminal.

I have plans for working in all of javascript, python and mono.NET, but since mono tends to be something of a beast, I'm going to get started with js/py only.


4.0 web server

// nginx
$ sudo apt-get install nginx

4.1 persistence


4.1.1 mongodb


32-bit version @ 2.6.10

- database limited to 2GB in size

// install
$ sudo apt-get install mongodb

// launch shell
$ sudo mongo

4.1.1 postgresql


$ sudo apt-get install postgresql


4.2 python /django web server stack

python3 (pre-installed)

// django web server
$ sudo apt-get install python-django

4.3 javascript / nodejs / express web server stack


4.3.1 nodejs & package management


$ sudo apt-get install nodejs
$ sudo apt-get install npm
$ sudo apt-get install bower

4.3.2 persistence

$ sudo npm install -g pg
$ sudo npm install -g mongo
 
5.0 install infosec tools

5.1 scapy wifi tools

// scapy dependencies

// python crypto
$ sudo apt-get install python-crypto

// python graphics
$ sudo apt-get install python-pyx

$ sudo apt-get install gnuplot
$ sudo apt-get install python-gnuplot

// scapy
$ sudo apt-get install python-scapy

5.2 reaver
 
$ sudo apt-get install reaver

5.3 pyscard = python smartcard

// python 2
$ sudo apt-get install python-pyscard
// python 3
$ sudo apt-get install python3-pyscard