Posts Tagged ‘linux’

Simple hdmi activate script

This is a simple script I bound to ‘meta+F7’ to activate a second hdmi display I am using:

disper -l | grep $EXTERNAL
function on {
    disper -e -d $INTERNAL,$EXTERNAL -r 1920x1080,1920x1080
    touch $LOCK
function off {
    disper -s -d $INTERNAL -r auto
    rm -f $LOCK
if [ $? -eq 1 ]; then #there is no EXTERNAL, run single command
elif [ -f $LOCK ]; then


Parsing network stream into http request/response

The need was to convert the network stream into clear text http request/responses while doing some decoding of the response body. For instance:

request uri + queryString => response body

  1. Capture the stream – easy using tcpdump
  2. Filter the http stream – easy using wireshark with a tcp.port eq 80 filter
  3. Export http #1. using wireshark file -> export objects -> http. This works fine only for files. It does not work for POST requests. FAIL.
  4. Using tshark and a combination of -Tfields and -e parameters. Did not worked easily enough even if I suspect it would. FAIL.
  5. Using tcpflow:  tcpflow -r test.pcapng -ehttp. This generates some nice flows but it had some disadvantages: requests and responses are in different files and are flow sorted not time sorted. I think this can be overcome by writting a script which parses: report.xml using something like this. FAIL.
  6. Final idea was based on pcap2har which parses a .pcap file to a har. Some changes to and voila:'Flows=%d. HTTP pairs=%d' % (len(session.flows), len(session.entries)))
for e in sorted(session.entries, key=lambda x: x.ts_start):
    if e.request.msg.method == 'GET':
        print 'GET', e.request.url
    elif e.request.msg.method == 'POST':
        print 'POST', e.request.url, urlencode({k: v[0] for k, v in e.request.query.items()})
    if e.response.mimeType == 'application/octet-stream':
        print decode(e.response.text, options.password)
        print 'unknown:', e.response.mimeType, e.response.raw_body_length
    print '\n'
#write the HAR file


Ubuntu 16.04

I’we used ubuntu since edgy days and migrating from gentoo. Things got better each time, until they started getting worse or until I started to expect not to have to fix and patch each time. So now I don’t feel like giving any impression, just a list of bugs:

Searching for signal

For the last few years, one of the tool I have greatly used is a Huawei E587 modem. It’s a great little device which gave me a lot of freedom. Even if it is quite old, it outperforms, even without an external antenna any smartphone I used for tethering and especially my new Samsung Galaxy S5 Neo which, as a parenthesis, has one of the poorest software I have ever seen, reminds me of a circa 2000 windows pre-installed on a laptop and filled with junkware.

However, as many other devices, the reporting of signal strength is very simplistic. My goal was to be able to identify the best spot for the external antenna defined by the best signal strength.


Running chrome in docker with audio

The goal is to run google-chrome in a docker container with audio support. I did this trying to get skype.apk to run in archron since skype for linux does not support conferencing anymore. Even if running skype in archron did not seemed to work chrome runs flawlessly with audio support via pulse:

So here is the Dockerfile:

FROM ubuntu:14.04
RUN apt-get update && apt-get install -y wget pulseaudio && echo "deb stable main" > /etc/apt/sources.list.d/google-chrome.list && wget -q -O - | sudo apt-key add - && apt-get update && apt-get install -y google-chrome-stable
RUN rm -rf /var/cache/apt/archives/*
RUN useradd -m -s /bin/bash chrome
USER chrome
ENV PULSE_SERVER /home/chrome/pulse
ENTRYPOINT [ "google-chrome" ]

You can build your container using:

docker build -t len/chrome .

The run it using:

docker run -it -v /tmp/.X11-unix:/tmp/.X11-unix -e DISPLAY=$DISPLAY -v $HOME/Downloads/chrome:/home/chrome/Downloads -v /run/user/$UID/pulse/native:/home/chrome/pulse -v /dev/shm:/dev/shm --name chrome len/chrome


Ensure rPi connectivity

The problem: make sure I can connect to my raspberry pi B+ even if no network is available or network change.

The idea: set a static IP.

First some information:

  • running raspbian 8.0 (cat /etc/issue)
  • there is no need for a crossover UTP cable if you connect directly to the device you can use a normal cable
  • IP configuration is delegated from /etc/network/interfaces to the dhcpcd daemon. This is why the eth0 is set on manual.

I did not wanted to crash default config. Just wanted to ensure the device will be visible. So I just added an aliased (virtual) interface with a fixed ip:


# Include files from /etc/network/interfaces.d:
source-directory /etc/network/interfaces.d
auto lo
iface lo inet loopback
iface eth0 inet manual
auto eth0:0
allow-hotplug eth0:0
iface eth0:0 inet static
allow-hotplug wlan0
iface wlan0 inet manual
    wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
allow-hotplug wlan1
iface wlan1 inet manual
    wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

This is my /etc/network/interfaces. You can now use a normal UTP cable to connect directly to the PI or on the LAN by setting an IP in the same class:

ifconfig eth0 up

Please note that if you are on ubuntu and have a NetworkManager controlled interface you might need to disable auto-control by editing /etc/NetworkManager/NetworkManager.conf (see the unmanaged-devices section)




Create timelapse movie from shaked photos

The problem consist of creating a timelapse made of photos which have been taken with a camera which has been removed and attached to a tripod during a few months thus creating a lot of shaking. Solution, use hugin to align photos:

align_image_stack -v -a$1 -s 2 *.jpg
mkdir base
for i in $(find . -maxdepth 1 -name "*.tif"); do n=".$(echo $i | cut -f2 -d".").jpg"; convert $i $n && mv $n base; done
rm *.tif
cd base && mencoder -nosound -ovc lavc -lavcopts vcodec=mpeg4:mbd=2:trell:autoaspect:vqscale=3 -mf type=jpeg:fps=5 mf://*.jpg -o $1.avi && cd .. && mv base/$1.avi .


Resize a kvm disk image

1. From the vm, stop the vm:


2. From the host, resize the disk image:

qemu-img resize /virt/disk02.img +50G

3. From the host edit partition table

parted /virt/disk02.img
GNU Parted 2.3
Using /virt/disk02.img
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print free                                                       
Model:  (file)
Disk /virt/disk02.img: 107GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End     Size    Type     File system  Flags
        16.4kB  1049kB  1032kB           Free Space
 1      1049kB  51.5GB  51.5GB  primary  ext4         boot
        51.5GB  107GB   55.9GB           Free Space

(parted) rm 1                                                             
(parted) mkpart primary 1049kB -2G
(parted) print free                                                       
Model:  (file)
Disk /virt/disk02.img: 107GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End     Size    Type     File system  Flags
        16.4kB  1049kB  1032kB           Free Space
 1      1049kB  105GB   105GB   primary  ext4
        105GB   107GB   2000MB           Free Space

Yes: rm 1, since this only deletes partion information, not data. Then you recreate partition info on top of data.

4. From the guest, restart, then:

resize2fs /dev/sda1

Create a database of exif data

Create a database of exif data from photos using pyexiv2 and save it in a sqlite database for futher query:

(X)Ubuntu microphone mute/unmute script

The goal of this script was to have a simple script, binded with a shortcut which allows to mute/unmute all the microphones and to display a nice notification in the process. This is the simplest version working on xubuntu 14.04 with pulseaudio.

ACTION=1 #1 mute, 0 unmute
SCNT=$(pacmd list-sources | grep muted | wc -l)
MUTED=$(pacmd list-sources | grep muted | grep yes)
if [ $? == 0 ]; then
    notify-send -i microphone-sensitivity-medium "Microphone" "Unmutting $SCNT sources..."
    notify-send -i microphone-sensitivity-muted "Microphone" "Mutting $SCNT sources..."
#SRC=$(seq $SCNT)
SRC=$(pacmd list-sources | grep index | cut -d':' -f2 | tr -d ' ')
for i in $SRC; do
    #let s=$i-1
    pacmd set-source-mute $i $ACTION