Daniel Kahlenberg 573

user.letter

command word	user.letter
air	a
bat	b
cap	c
drum	d
each	e
fine	f

Table Of Content

Skip to the relevant sections if needed.

2-min tutorial to do it the quick-and-dirty-way
Concepts for resolving Git conflicts
Setting up different editors / tool for using git mergetool
- Finding out what mergetool editors are supported
mergetool simple code example for vimdiff
- Resolving conflict from a Git pull
Other great references and tutorials

Nix Flake MVP

Goals

To provide Nix repositories with an easy and standard way to reference other Nix repositories.
To allow such references to be queried and updated automatically.
To provide a replacement for nix-channel, NIX_PATH and Hydra

How to compress PDF using ghostscript

As a developer, it bothers me when someone sends me a large pdf file compared to the number of pages. Recently, I recieved a 12MB scanned document for just one letter-sized page... so I got to googlin, like I usually do, and found ghostscript!

to learn more abot ghostscript (gs): https://www.ghostscript.com/

What we are interested in, is the gs command line tool, which provides many options for manipulating PDF, but we are interested in compressign those large PDF's into small yet legible documents.

credit goes to this answer on askubuntu forum: https://askubuntu.com/questions/3382/reduce-filesize-of-a-scanned-pdf/3387#3387?newreg=bceddef8bc334e5b88bbfd17a6e7c4f9

PSQL

Magic words:

psql -U postgres

Some interesting flags (to see all, use -h or --help depending on your psql version):

-E: will describe the underlaying queries of the \ commands (cool for learning!)
-l: psql will list all databases and then exit (useful if the user you connect with doesn't has a default database, like at AWS RDS)

	{
	inputs = {
	nixpkgs.url = github:nixos/nixpkgs/nixos-unstable;
	flake-utils.url = github:numtide/flake-utils;
	rust-overlay.url = github:oxalica/rust-overlay;
	};

	outputs = { nixpkgs, flake-utils, rust-overlay, ... }:
	flake-utils.lib.eachSystem ["x86_64-linux"] (system: let
	pkgs = import nixpkgs {

	:def hoogle \x -> return $ ":!hoogle --count=15 \"" ++ x ++ "\""
	:def doc \x -> return $ ":!hoogle --info \"" ++ x ++ "\""
	:set -Wall
	:set -fno-warn-type-defaults -ferror-spans -freverse-errors -fprint-expanded-synonyms
	:set prompt "\ESC[0;32m%s\n\ESC[m[ghci]\ESC[38;5;172mλ \ESC[m"
	:set prompt-cont " \ESC[38;5;172m> \ESC[m"

	package com.github.therapi.apidoc;

	import java.util.List;

	import com.fasterxml.jackson.databind.JavaType;
	import com.fasterxml.jackson.databind.ObjectMapper;
	import com.fasterxml.jackson.module.jsonSchema.JsonSchema;
	import com.fasterxml.jackson.module.jsonSchema.factories.SchemaFactoryWrapper;
	import com.fasterxml.jackson.module.jsonSchema.factories.VisitorContext;

	{ pkgsPath ? <nixpkgs> }:
	let
	pkgs = import pkgsPath {};
	pkgsAarch64 = import pkgsPath { system = "aarch64-linux"; };

	iso = (pkgsAarch64.nixos {
	imports = [ (pkgsPath + "/nixos/modules/installer/cd-dvd/installation-cd-base.nix") ];
	users.users.root.openssh.authorizedKeys.keyFiles = [(builtins.fetchurl https://github.com/lheckemann.keys)];
	}).config.system.build.isoImage;