Tucker Chapman

Generate Random String with CLI

Mon, 03 Aug 2026 00:00:00 +0000

TIL a few one-liners for generating random strings.

date +%s | sha512sum | base64 | head -c 24 ; echo

The string is pseudo random and seeded by the current UNIX timestamp. The command should work with most Linux distros and MacOS. If running on Linux a more random command to try uses /dev/urandom and tr.

tr -dc A-Za-z0-9 </dev/urandom | head -c 24; echo

If you need a passphrase you can use the dictionary file to select n random words.

Firefox Address Bar Shortcuts

Thu, 23 Jul 2026 00:00:00 +0000

TIL The Firefox Address Bar includes shortcuts for all kinds of things. Use special characters to search your history (^), bookmarks (*), and tabs (%). Type the shortcut character before your search to filter the dropdown entries to tab through. Use the @ to search configured websites, history, bookmarks, and tabs (type @bookmarks, @wikipedia, etc.). Add keywords to your bookmarks to create shortcut for your favorite sites (e.g. “wiki” to go to Wikipedia). For the cherry on top, use Ctrl + L (Cmd + L) to focus on the address bar.

JWTs are Base64URL Encoded Strings

Sat, 18 Jul 2026 00:00:00 +0000

TIL a JWT (JSON Web Token) is a couple Base64URL encoded strings with a signature. A JWT takes the structure <header>.<payload>.<signature>. The header and payload of a JWT aren’t secret (they’re Base64URL encoded). The magic of JWTs is how the signature is calculated. Calculate the signature by Base64URL encoding the header and payload then hashing with a secret HMACSHA256(base64UrlEncode(header) + "." + base64UrlEncode(payload), secret). Modifying the header or payload changes the signature–making the data untrustworthy.

Proactively Lazy

Thu, 09 Jul 2026 09:06:52 -0400

Get more done by embracing laziness. Motivation—the fickle beast—doesn’t make you productive, your interaction with your environment does. Use your motivation to improve the environment by reducing—or increasing—the energy needed do things. Clean the dishes as soon as you finish your meal, display your guitar on a stand instead of in the closet, log out of all social media accounts when you finish scrolling. James Clear, in his book Atomic Habits, quoted Oswald Nuckols who said, “People think I work hard but I’m actually really lazy. I’m just proactively lazy.” Use your motivation energy to reduce the “activation energy” of productivity by improving your environment. Embrace your laziness—proactively.

Helpful Vim Ex Mode Commands

Sat, 04 Jul 2026 09:52:12 -0400

Simple patterns to do useful things with the Ex Mode :global command in Vim

Delete all lines that match a pattern (:help pattern)

:g/pattern/d
:global/pattern/delete

Delete all lines that don’t match a pattern (:help :vglobal)

:g!/pattern/d
:v/pattern/d
:vglobal/pattern/delete

Remove all trailing whitespace with :substitute

:%s/\s\+$//e

Find more info by running :help :global and :help :substitute

SQL Simple Pivot Pattern

Sat, 06 Sep 2025 13:16:24 -0400

TIL a simple pattern for pivoting data with an SQL query using FILTER (or a CASE WHEN clause if the FILTER keyword isn’t supported by the database). The example input data is from the Chinook Database and is modeled like this:

| InvoiceDate         | BillingCountry | Total |
| ------------------- | -------------- | ----- |
| 2011-02-15 00:00:00 | Belgium        | 1.98  |
| 2009-10-17 00:00:00 | Brazil         | 13.86 |
| 2009-03-05 00:00:00 | USA            | 3.96  |
| 2012-09-05 00:00:00 | Czech Republic | 16.86 |
| 2012-10-27 00:00:00 | India          | 1.98  |
| 2012-08-27 00:00:00 | Hungary        | 3.96  |
| 2011-07-25 00:00:00 | Canada         | 8.91  |
| 2012-06-25 00:00:00 | USA            | 1.98  |
| 2012-02-22 00:00:00 | Poland         | 1.98  |
| 2013-03-05 00:00:00 | Italy          | 8.91  |

A pivot query using FILTER (with a SQLite db)

Interpolate Environment Variables with Docker Compose

Fri, 11 Apr 2025 08:45:08 -0400

TIL you can use environment variables in your docker compose files. I use environment variables with my homelab setup as a simple way to keep secrets out of version control and reduce repeating common file paths for binded volumes. Docker compose even uses a .env file out of the box. Most shell interpolation features work too.

services:
  web:
    image: nginx
    ports:
      - "8080:${NGINX_PORT:-80}"
    environment:
      - NGINX_HOST=${NGINX_HOST:?error}
      - NGINX_PORT=${NGINX_PORT:-80}

Reference: Environment Variables in Compose

Create multiple nvim configs with $NVIM_APPNAME

Sat, 08 Feb 2025 09:58:19 -0500

TIL you can save multiple nvim config setups with the $NVIM_APPNAME environment variable. Nvim will look for, or create, the config in the $XDG_CONFIG_HOME/$NVIM_APPNAME directory. Easily switch between the configs with aliases in the startup file for your shell (i.e. .bashrc, .zshrc, etc.).

# $NVIM_APPNAME defaults to nvim
alias avim='NVIM_APPNAME="nvim-astro" nvim'
alias zvim='NVIM_APPNAME="nvim-lazy" nvim'
alias kvim='NVIM_APPNAME="nvim-kickstart" nvim'

Source: $NVIM_APPNAME docs

Exclude Directories using the Find command

Thu, 18 Jan 2024 15:03:16 -0500

TIL you can exclude directories when using the find command.

## Exclude the node modules directory when searching with find
find ./ -name "*.css" ! -path "*/node_modules/*"

Source: Stack Overflow

Python Http Server

Thu, 18 Jan 2024 13:26:06 -0400

Python comes with a simple http server you can use to serve a directory of files as a web server. I use it all the time to serve code coverage reports and various other static web projects that don’t come with a server. Start the server using this command:

$ python -m http.server
Serving HTTP on :: port 8000 (http://[::]:8000/) ...

Once this is running you can now access the files in the directory with your web browser (at http://localhost:8000).

Python Context Manager

Thu, 21 Sep 2023 09:37:02 -0400

TIL you can write your own functions to use in a python with statement. These functions are called context managers. A context manager is a simple way to wrap a try/except/finally block in a reusable function.

Writing your own context manager is simple.

from contextlib import contextmanager

@contextmanager
def random_number():
    """ https://xkcd.com/221/ """
    try:
        # do any setup
        yield 4 # Yielded objects can be accessed from the `var` after the `as` keyword
    except:
        # handle any errors
        pass
    finally:
        # Clean up here (e.g. close db connections or open files)
        pass

## Call the context manager like this
with random_number() as n:
    # do something with `n`
    print(n)

PEP-343 has some other context manager examples.

Podman Pods

Sat, 20 May 2023 18:40:22 -0400

TIL the POD in Podman is the same idea as Pods in Kubernetes. Pods are collections of containers that share resources (i.e. volumes, networks, etc.). Create a pod with the podman pod create --name [pod-name] command. You will need to expose ports and setup other resources with the pod create command.

podman pod create --name my-new-pod --infra --publish 8080:80 --network bridge

Add a container to a pod with the --pod [pod-name] flag in your run command:

Special tld '.home.arpa'

Tue, 03 Jan 2023 11:04:54 -0500

TIL about the special-use *.home.arpa tld. The .home.arpa tld is reserved for “non-unique residential home networks”. If you use Adguard Home, Pi-Hole, or any other DNS server you can freely use .home.arpa for all your local assets (printers, self-hosted server, etc.)!

Slash or Not to Slash with rsync

Sat, 26 Nov 2022 00:00:00 +0000

TIL an easy way to remember if you want a slash or not when you run rsync. A trailing slash will copy the contents of the directory while just the directory name will copy the directory itself. For example

# copies everything in dir into new-dir
rsync -r dir/ new-dir

# copies dir into new-dir
rsync -r dir new-dir

Python List Comprehensions

Fri, 25 Nov 2022 00:00:00 +0000

TIL about Python List Comprehensions. I came across code that looked like this in a codebase.

baz = [foo.bar for foo in foos]

I could see what was happening (baz is now a list of bar for each object in foos). I didn’t know this was called list comprehension but now I understand the data structure.

List comprehensions are useful for lots of things when you want to create lists from other objects (docs source).

Hugo Debug Jsonify

Sun, 13 Nov 2022 16:54:29 -0500

TIL that you can output all the data in “the dot” from a Hugo template using jsonify

<pre>{{ . | jsonify (dict "indent" "  ") }}</pre>

Here is the output of the .Params value for this post

<pre>{{ .Params | jsonify (dict "indent" "  ") }}</pre>

{
	"date": "2022-11-13T16:54:29-05:00",
	"draft": false,
	"iscjklanguage": false,
	"lastmod": "2022-11-13T16:54:29-05:00",
	"publishdate": "2022-11-13T16:54:29-05:00",
	"tags": ["hugo", "ssg", "debug"],
	"title": "Hugo Debug Jsonify"
}

cal and ncal

Tue, 08 Nov 2022 00:00:00 +0000

TIL about ncal (most Linux distros) or CAL (on MacOS). I have used cal for quite a while which is a convenient calendar tool in the terminal. However, I hit CAPS LOCK on accident and ran CAL instead of cal, to my surprise it output

    November 2022
Mo     7 14 21 28
Tu  1  8 15 22 29
We  2  9 16 23 30
Th  3 10 17 24
Fr  4 11 18 25
Sa  5 12 19 26
Su  6 13 20 27

(the normal cal output)

How to Open Files with Vim

Tue, 16 Feb 2021 00:00:00 +0000

How exactly do you open a new file without closing and reopening vim? Read on to learn more about how to open files (or buffers) in vim using various included tools or external plugins. Vim uses the word “buffer” instead of “file”. When you :wq you write the current buffer to a file.

Getting started with vim-airline

Tue, 15 Sep 2020 00:00:00 +0000

The default vim status line can work well but vim-airline inhances it in many ways. Vim-airline is a simple lightweight plugin that integrates with many other popular plugins out of the box (but they are not required). In this post you will learn how to get vim-airline setup with some basic settings and a theme.

Vim Plugin Audit

Mon, 18 May 2020 00:00:00 +0000

Vim is my daily driver for text editing. I keep my plugin list curated to only what I use on a regular basis. In this post I’m going to go over each plugin currently in my plug file, write a sentence about it, and determine whether is stays or goes.

Roland FP-30 and Bluetooth

Mon, 11 May 2020 00:00:00 +0000

This may work on other Roland digital piano models but I only tested it on an FP-30 with my Motorola X4. After spending about an hour trying to figure out why my system Bluetooth could not find my piano I figured out how to actually connect. (Hint: it’s not through the system Bluetooth)

Download the Roland Piano Partner 2 App
Turn on your piano
Enable Bluetooth on your phone
Turn on the Piano Bluetooth feature (on the FP-30 you hold the function/Bluetooth button and press A0)
Open the Piano Partner App
Tap the Gearbox in the top right corner
Tap “Bluetooth MIDI Device”
Tap “SCAN” (Potentially not needed step)
Select your piano from the list (FP-30 in my case)
A Successful connection is when an * shows up next to the name
Go “Back” on your phone (tap the triangle in Android 9.0)
You will see a “Preparing Data” loading bar show up
Success you are now connected to your piano
Practice.

This is confusing and I could not find how to do it in the manual or online but an hour of trouble shooting got me to these steps. If it’s not helpful to anyone else out there at least now I have it written out for myself.

Vim Has Spell Check!?

Sun, 10 May 2020 00:00:00 +0000

Did you know vim has a build in spell check system? The built in spell system will ignore code variable names and functions by default but it does detect spelling mistakes in your comments and doc blocks (you do write helpful comments right?).

A Better Way to Organize Your .vimrc

Sat, 09 May 2020 00:00:00 +0000

Vim is a powerful customizable editor. Configuration is stored in custom text files often found in a Unix home directory (ie ~/.vimrc). This vimrc file can get to be rather large the longer one uses vim.

Break the file into parts

The number of files you use is infinite but it works best to keep things simple and organized. I use five files: plugin loader, general settings, leader key settings, custom functions, and plugin specific settings. Source each of these in your main vimrc $HOME/.vimrc. The $HOME/.vim/init directory is not used by vim so I keep my files there.

How to Use the Vim Key

Sat, 16 Jun 2018 00:00:00 +0000

Vim is a keyboard driven text editor which means there are a lot of keyboard shortcuts and commands. The <leader> key is a vim tool that can be used to create personalized shortcuts. Let’s discuss a few different ways to create our own shortcuts.

Refactoring a Rails View

Sun, 20 May 2018 00:00:00 +0000

Have you ever looked back on your code and thought “Who wrote this! ….<git blame>…oh…it was me.” We are all constantly learning new things and frankly our past self is just not as smart as our current self (or so we think). So today I want to walk through a simple refactor I did on a Rails project I have worked on over the years. (Source code found on my GitHub)

Qgis Tutorial – Earthquakes in Oklahoma

Tue, 04 Apr 2017 00:00:00 +0000

Download your own copy of QGIS from qgis.com (works on Windows, MacOS X, and Linux)

Overview of the Interface

Welcome to QGIS! Quantum GIS (now just known as QGIS) is a cross-platform, free, and open source GIS application. It has all of the features one needs in a GIS and many more can be added simply using the community hosted plugin repository. The QGIS UI Reference Image can be used to get yourself situated if you are familiar with the ArcMap for Desktop UI.