Entries tagged 'lang:en' (Page 37)

SBWG 0.8.10

Entry created on 2021-05-24 author:steeph (374) cat:Bash (31) cat:Code (31) cat:Computer (78) cat:Linux (36) cat:Projects (41) cat:SBWG (18) cat:Scripts (28) cat:Software (53) lang:en (253) top:Projects:Code:Bash Scripts:SBWG (16)

So, I'm still making slow process with SBWG. I had more fun with it when I was out and implementing new features. But I find it important to finish version 1.0.0 with the currently defined set of festures and goals, which include finishing documentation, testing and code hardening, which are less fun for me.

I've always treated the third level of the version number (x.x.thisone) as a means to declare a new version done when I feel like having achived something. So today I declare version 0.8.10 as done. There really isn't much left to do to meet my milestones for v0.9.0. And from there on it will only be testing and possibly a little bit of code improvements to get to my set goals for v1.0.0.

I'm looking forward to this not only because I'll like the feeling of having achived a goal, but also it will mean that I'll be free again to introduce new features. I still have more ideas than necessary about what to do with SBWG.

But right now I'm enjoing the fact that I'm able to make myself believe that it's okay to move on as slowly as I want and let my colloquial executive dysfunction do its think without impacting my feeling of self-worth oo much.

Project Idea: Liquid Clock

Entry created on 2021-05-24 author:steeph (374) cat:Clocks (2) cat:Projects (41) cat:Water (1) lang:en (253) top:Projects:Ideas (8)

I've had a few ideas about unconventional types of clocks that could be built that don't work with the two well-known principles of a digital number display or an analogue display of rotating hands. I believe that with enough practice/training one could learn to read very different kinds of clocks by just looking at them shortly.

One of these ideas involves liquids. It's a quite unnecessarily complex way to display the time but it would probably be relatively easy to learn to read this one. I highly doubt that I will ever build a clock like this. So I'm writing down my idea in the hopes that I'll then be able to stop thinking about it every other day.

Without trying to be compact, the clock would be made of several pumps and transparent tubes mounted on a board. The main part of the display (the part you'd use to tell the time) would be three vertically oriented tubes mounted next to each other, each with an open top (or an air valve to keep dirt out). Below them there would be a small tank that contains a colored fluid. This fluid would be transported by a pump to one of the tubes at the top. One tube would display hours, one minutes and one would be used for seconds. At the full minute, the third tube would be emptied by the pump. Then a equal amount of the colored liquid would be pumped up the tube until the next minute is up and it's emptied again. The same principle would apply for the second tube: It slowly rises at a constand speed and is emptied at the full hour. You can image how the first tube would be filled. It would either be emptied every 12 or every 24 hours, which I would prefer.

On the board one could mark certain points of the tubes (like every hour the the first one, every minute for the second one, ...) to make it easier to tell the exact time.

There could be one pump and some valves to control with tube will get how much fluid. Or there could be three independent pumps, one for each tube.

That's actually a much simplified version of my initial idea. You could (at least in theory) build a closed loop that contains as little air as possible and does not have the risk of ingesting dirt over the time. In the reservoir/equalising tank there could be two separate fluids, e.g. red water and blue or transparent oil. Those two fluids would stay separated in the equalising tank and either of the fluids could be fetched at will by pumping from a low or high place of the tank. This way much more elaborate patterns could be created in theory. But if the board had a color with hight enough contrast to the fluids colour, that should be enough to be able to tell the time and it would be less error-prone to do it the simple way.

That's it. Unnecessary, never-to-be-built, just an idea.

Bash script to burn your CPU easily

Entry created on 2021-05-16 author:steeph (374) cat:Bash (31) cat:CPUs (5) cat:Code (31) cat:Computer (78) cat:Scripts (28) cat:Software (53) lang:en (253) top:Projects:Code:Bash Scripts (23)

When making my own CPU cooler or testing some other stuff I sometimes need to create as high of a CPU load as possible. After typing while true; do true; done for the one-too-manyth time I finally decided to create an alias for that. But that didn't feel neat enough. So I made this simple Bash script.


#!/bin/bash

if [ "$#" -ne "1" ]
then
  echo "I need one argument and one argument only: Number of threads to start."
  echo "Hint: You have $(nproc) CPU cores."
  exit 1
fi

if [[ "$1" =~ ^[0-9]+$ ]]
then
  n="$1"
else
  echo "Argument needs to be a number: Number of threads to start."
  echo "Hint: You have $(nproc) CPU cores."
  exit 1
fi

trap "pkill -P $$; exit 0" SIGHUP SIGINT SIGTERM

while [ "$n" -gt 1 ]
do
  while true; do true; done &
  n=$((n-1))
done
echo "Started $1 threads to burn your CPU."
pidof -x "$(basename -- $0)"
while true; do true; done

Download

For a simpler script, you can also just use this three-liner without any arguments to stress all CPU cores:


#!/bin/bash
yeah() { while true; do true; done& }
threads=$(nproc)
for i in $(seq 1 $threads); do yeah; done

Entry created on 2021-05-09 (edited 2021-05-15) author:steeph (374) cat:Alcohol (1) cat:Thoughts (71) lang:en (253)

I'm drunk. Sorry.

Edit: I hardly remember making this entry. But my guess is that I had a subjectively good reason. So I'm leaving it here even if I don't know what it is referring to. (I don't even know how sorry I was.)

Bash script to quickly open and close a wifi hotspot

Entry created on 2021-05-15 author:steeph (374) cat:Bash (31) cat:Code (31) cat:Computer (78) cat:Scripts (28) cat:Software (53) cat:WiFi (1) lang:en (253) top:Projects:Code:Bash Scripts (23)

I needed a wifi hotspot to test some phones. So I looked up how to create one quickly and learned about nmcli. It wasn't quick and easy enough for my taste. So here is how I do it from now on.

The Bash script maintains only one connection (named quick-hotspot). You can't create multiple connections or access points with it. Not intentionally, but also not accidentally because you forgot that you still have a hotspot enabled from the last time you needed one. (I know I would at some point.)

Examples:


hotspot # Creates and enables a hotspot with a random name and a random 8-digit password.
hotspot down # Disables the hotspot if it was enabled.
hotspot ⊿ⴼͳΞⵖⵡ∃ doctorwho # Creates and enables a hotspot with the SSID "⊿ⴼͳΞⵖⵡ∃" and the password "doctorwho".
hotspot . password # My use case: quick and short and I don't want to type a complicated password on the phones. SSID: ".", PW: "password"
hotspot down # Deactivates the hotspot regardless of the SSID you used.

If you activate a hotspot while one is already active, it just changes the SSID and password so that no two connections created by this script are ever active at the same time. I'm sure there already is a program that solves this better. But it was fun for me to create and I felt like sharing.

Click here to download the bash script.

Content:

#!/bin/bash

# Quickly create and activate a WiFi hotspot - optionally defining SSID and password - and deactivate it again when you don't need it anymore.

usage() {
  echo "Usage: $(basename $0) ssid passphrase"
  echo "       $(basename $0) down"
  echo "       $(basename $0)"
  exit 1
}

activate() {
  # If the connection "quick-hotspot" doesn't already exist...
  if ! nmcli connection show | grep quick-hotspot; then
    # ... then create it.
    nmcli connection add type wifi ifname '*' con-name quick-hotspot autoconnect no ssid "$ssid"
  else
    # ... else change the SSID of the existing connection.
    nmcli connection modify quick-hotspot ssid "$ssid"
  fi
  # Make the connection an access point
  nmcli connection modify quick-hotspot 802-11-wireless.mode ap 802-11-wireless.band bg ipv4.method shared
  # Change the password
  nmcli connection modify quick-hotspot 802-11-wireless-security.key-mgmt wpa-psk 802-11-wireless-security.psk "$pw"
  # Enable the connection
  nmcli connection up quick-hotspot
}

case $# in
  0)
    ssid=$(</dev/urandom tr -dc A-Z] | head -c8; echo "")
    echo "SSID: $ssid"
    pw=$(shuf -i 10000000-99999999 -n 1) 
    echo "PW: $pw"
    activate
    ;;
  1)
    if [ $1 == down ]; then
      nmcli connection down "quick-hotspot"
      exit 0
    else usage
    fi
    ;;
  2)
    ssid="$1"
    if ! [ ${#2} -ge 8 ]; then
      echo "$(basename $0): Password needs to be 8 characters or longer."
      exit 1
    else
      pw="$2"
      activate
    fi
    ;;
  *)
    usage
    ;;
esac