elix7r

Debian 13

Caution Upgrading from Debian 12 to Debian 13 on machines with mdadm has intermittently failed for me; symptom is that grub EFI is not up to date and system boots into BIOS. Root cause under investigation; it might not be related to mdadm.

To start, read the official release notes.

If your install fits into "vanilla Debian plus maybe a handful of 3rd-party repos", then this guide for a simple upgrade to Debian 13 "trixie" from Debian 12 "bookworm" can be helpful. 3rd-party repos are handled with a find command.

Note upgrade is only supported from Debian 12 to Debian 13. If you are on Debian 11, upgrade to Debian 12 first. Then once on Debian 12, you can upgrade to Debian 13.

About

I faced bandwidth issues between a WG Peer and a WG server. Download bandwidth when downloading from WG Server to WG peer was reduced significantly and upload bandwidth was practically non existent.
I found a few reddit posts that said that we need to choose the right MTU. So I wrote a script to find an optimal MTU.
Ideally I would have liked to have run all possible MTU configurations for both WG Server and WG Peer but for simplicity I choose to fix the WG Server to the original 1420 MTU and tried all MTUs from 1280 to 1500 for the WG Peer.

Testing

On WG server, I started an iperf3 server
On WG peer, I wrote a script that does the following:
- wg-quick down wg0
Edit MTU in the /etc/wireguard/wg0.conf file

ELF Format Cheatsheet

Introduction

Executable and Linkable Format (ELF), is the default binary format on Linux-based systems.

Compilation

Потоки	Горутины
Потоки ОС управляются ядром ОС	Горутины управляются "рантаймом" Go
Потоки ОС в основном имееют фиксированый размер в 1-2MB	Горутины обычно имеют размер стэка 2KB
Размер стэка определяется во время компиляции и не может увеличиватся	Размер стэка определяется во время рантайма и может расти вплоть до 1GB что возможно благодаря аллокации и освобождения места из хипа
У потоков нету простого способа коммуникации между собой. Такая коммуникация имеет большую задержку	Горутины используют "каналы" для быстрого общения между собой с маленькой задержкой

OpenSSL Cheat Sheet 🔐

Install

Install the OpenSSL on Debian based systems

sudo apt-get install openssl

Removing the last commit

To remove the last commit from git, you can simply run git reset --hard HEAD^ If you are removing multiple commits from the top, you can run git reset --hard HEAD~2 to remove the last two commits. You can increase the number to remove even more commits.

If you want to "uncommit" the commits, but keep the changes around for reworking, remove the "--hard": git reset HEAD^ which will evict the commits from the branch and from the index, but leave the working tree around.

If you want to save the commits on a new branch name, then run git branch newbranchname before doing the git reset.

ORIGINAL did fork but search didn't helped me

Docker Commands, Help & Tips

Show commands & management commands

$ docker

Docker version info

README

The example below creates a TCP server listening on a stream (i.e. SOCK_STREAM) socket. A similar approach can be followed to create a UDP server on a datagram (i.e. SOCK_DGRAM) socket. See man systemd.socket for details.

An example server

Create an simple echo server at ~/tmp/foo/serve.py.

	# Create a new worktree and branch from within current git directory.
	ga() {
	if [[ -z "$1" ]]; then
	echo "Usage: ga [branch name]"
	exit 1
	fi

	local branch="$1"
	local base="$(basename "$PWD")"
	local path="../${base}--${branch}"

	# Temporarily add a normal upstream DNS resolver
	/ip dns set servers=1.1.1.1,1.0.0.1

	# CA certificates extracted from Mozilla
	/tool fetch url=https://curl.se/ca/cacert.pem

	# Import the downloaded ca-store (127 certificates)
	/certificate import file-name=cacert.pem passphrase=""

	# Set the DoH resolver to cloudflare