I’ve used https://textik.com and I like it.
http://asciiflow.com/ has some different features, and although it seems like it has some capabilities that textik doesn’t have (like adjusting some of the objects), I like textik.com better.
Once I’ve got my basic diagram done in textik, I use vim to further adjust it and move things around. I paste the diagrams into Confluence or other documentation.
Here’s how I recorded my screen, with audio from the microphone, from my Ubuntu 20.04 machine:
sleep 10 && ffmpeg -video_size 1920x1080 -framerate 25 -f x11grab -i :0.0+0,0 -f pulse -ac 2 -i default ~/Videos/screencast.mp4
Reference: https://trac.ffmpeg.org/wiki/Capture/Desktop
I’m documenting this more for my own reference than anything, partly because I’ve used ‘tc’ off and on over the years.
tc qdisc add dev tun0 root netem loss 30%
tc qdisc show dev tun0
tc qdisc change dev tun0 root netem loss 0.1%
When finished:
tc qdisc del dev tun0 root
I organize images in a custom hierarchy of directories. Lately, I’ve been using Google Photos and its shared albums to share photos with family. When I download the photos from the album that others have contributed, I want to organize those photos based on who contributed them. Google photos doesn’t make that easy.
Fortunately, cameras embed their make and model into each picture that they take, and since nearly everyone uses a different model of smartphone or camera, it is easy to separate out the images.
Windows Explorer allows me to add the model of the camera for an image in the details view. Then I can sort on the model, and break out the photos into a separate subdirectory for each contributor.
On Linux, I haven’t found an easy way to do the same thing — i.e. Gnome’s file manager, Nautilus, is anemic in comparison, as are other Linux alternatives.
Recently, I found exiftool, and it solves the problem for me, at a command-line level (it works on Windows, MacOS, Linux, BSD, and others).
Test adding the model of camera to image (e.g. Canon EOS Rebel XIV)
exiftool -p -v1 '-testname<$model %f.%e' *.jpgDo it for real:
exiftool -p -v1 '-filename<$model %f.%e' *.jpgThe final task is to remove the model name from the image. E.g.
rename 's/Canon EOS Rebel XIV //' *.jpgExiftool can do so much more, including organize images into subdirectories. This examples organizes images in the current directory into year-month-date directories:
exiftool -preserve -d "%Y-%m-%d" "-directory<filemodifydate" "-directory<createdate" "-directory<datetimeoriginal" .
From the world of interesting and cool approaches to solving software deployment issues:
Statically linked binaries that minimize dependency management difficulties work well for C++ executables, but languages like Python, JavaScript, and even Lua present a different challenge: How do you place source code and data (such as SSL certificates or shared libraries) inside a single executable? What do you do about the dependencies the tool might have on modules installed on the host operating system?
XARs are slightly modified squashfs files… that mount themselves when executed and unmount after an idle timeout. They could almost be thought of as a self-executing container without the virtualization. By using the squashfs format, we not only distribute data in a … compressed format…, but we also decompress on demand only the portions we need. Thanks to this architecture, XARs have nearly zero overhead in production and can be used just as native scripts or executables would be.
At work, we generate quite a few feature branches, which get tested, and then merge into “develop”. The feature branches don’t get cleaned up frequently. Here’s a series of shell commands I cobbled together to show the most recent person to commit to the branch, and which branches have been merged into develop.
git checkout develop
git pull -r
(for branch in $(git branch -r --merged | grep -vP "release|develop|master") ; do git log -1 --pretty=format:'%an' $branch | cat ; echo " $branch" ; done) | sort | sed -e 's#origin/##'
The output looks something like this:
Jane Doe feature/something
Jane Doe feature/another-thing
Jane Doe feature/yet-another-something
Zane Ears feature/howdy
And they can be deleted as follows:
git push origin --delete feature/something
I have some WiFi cameras that can be added to a router via WPS. Here’s how I got it to work with one of my LEDE routers. On the other one, somehow, I broke its ability to do WiFi completely, so this can be dangerous — I had to re-install LEDE. YMMV.
OpenWRT/LEDE Instructions:
First, backup the router config — always a good idea!
Setup:
opkg update
opkg remove wpad-mini
opkg install wpad hostapd-utils
opkg upgrade dnsmasq
cp /etc/config/wireless /etc/config/wireless.orig
vi /etc/config/wireless and change wps_pushbutton to '1' -- but only for one interface.
reboot
Check to see if WiFi is working. If not, use the ethernet port connected to a laptop to log back in, and update the firmware that isn’t broken. There may be a better way, but that’s worked for me.
Put the router into WPS mode (note: this times out after a while):
hostapd_cli wps_pbc
Other instructions say to run this (YMMV):
hostapd_cli -i wlan1 wps_pbc
Within a minute or so, push the WPS mode button on the camera.
Install supporting software
sudo apt-add-repository ppa:yubico/stable
sudo apt-get update
sudo apt-get install scdaemon -y
sudo apt-get install python-setuptools python-crypto python-pyscard python-pyside pyside-tools libykpers-1-1 pcscd -y
sudo apt-get install yubioath-desktop yubikey-personalization yubikey-personalization-gui yubikey-manager -y
Insert Yubikey and Generate key
gpg --card-edit
gpg/card> admin
gpg/card> generate
gpg/card> quit
export and backup the public keys, because the Yubikey only stores the private portion of the key
gpg --armor --export $KEYID > mykey.pub
Require touching the Yubikey button to authenticate, sign, or encrypt:
ykman openpgp touch aut on
ykman openpgp touch sig on
ykman openpgp touch enc on
Change the pin
gpg --card-edit
gpg/card> admin
gpg/card> passwd
gpg/card> quit
Change yubikey information
gpg --card-edit
gpg/card> name
gpg/card> lang
gpg/card> quit
References:
I’ve had what I thought was a great WiFi router for the past 3 years. The vendor continues to provide firmware updates, which is admirable.
Having heard of the awesome improvements that are being made by folks in the LEDE fork of OpenWRT (in the area of eliminating bufferbloat), I thought it was time for an upgrade. So I purchased an Archer C7 version 2 router, and today, I installed LEDE. Installation was a breeze. Configuring LEDE isn’t as easy as most consumer WiFi routers, but the payoff has been good.
My downstream 2GHz WiFi cameras and networking gear seem to be staying online better, and streaming live video works better as well. I’m not sure if my family notices much of a difference, but I do. I appreciate the folks who have brought me better networking.
Sometime in the distant past, I was aware of Universal Plug and Play (UPnP), but I didn’t know much about it. It’s a technology that allows devices in the home to talk to each other without prior configuration — it allows auto-discovery and configuration of printers and media servers, among other things.
The auto-discovery happens via SSDP (Simple Service Discovery Protocol). A device joins a network and announces “I’m here!”, and then other device can choose to respond. Even if the device gets a different IP address, it can still be uniquely identified by its unique identifier (UUID).
Here’s more information about UPnP and related protocols that run on the home network:
https://en.wikipedia.org/wiki/Zero-configuration_networking
UPnP:
UPnP protocol (no authentication):
UPnP has well defined device profiles for:
Routers:
Internet Gateway Device Protocol
Retrieve external IP addr
Devices Profile for Web Services (DPWS)
Other protocols that help on the home network:
Apple’s Bonjour uses mDNS and DNS-SD. Linux’s Avahi uses IPv4LL, mDNS, and DNS-SD. Linux’s systemd has “systemd-resolve”, a command-linetool to resolve hostnames on a network via DNS, mDNS, and LMMNR.