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Arch Linux Full-Disk Encryption Installation Guide

This guide provides instructions for an Arch Linux installation featuring full-disk encryption via LVM on LUKS and an encrypted boot partition (GRUB) for UEFI systems.

Following the main installation are further instructions to harden against Evil Maid attacks via UEFI Secure Boot custom key enrollment and self-signed kernel and bootloader.

Preface

You will find most of this information pulled from the Arch Wiki and other resources linked thereof.

Note: The system was installed on an NVMe SSD, substitute /dev/nvme0nX with /dev/sdX or your device as needed.

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security and hardening options for systemd service units

A common and reliable pattern in service unit files is thus:

NoNewPrivileges=yes
PrivateTmp=yes
PrivateDevices=yes
DevicePolicy=closed
ProtectSystem=strict

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How to mount a qcow2 disk image

This is a quick guide to mounting a qcow2 disk images on your host server. This is useful to reset passwords, edit files, or recover something without the virtual machine running.

Step 1 - Enable NBD on the Host

modprobe nbd max_part=8

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Reload the DNS Cache in Network Manager

You may be using NetworkManager with dnsmasq as the DNS plugin. If so, it's being used as a local caching nameserver.

When its data is outdated, you can force it to reload its DNS cache with:

Use:

nmcli general reload dns-full

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How to recover a dropped stash in Git?

1. Find the stash commits

git log --graph --oneline --decorate ( git fsck --no-reflog | awk '/dangling commit/ {print $3}' )

This will show you all the commits at the tips of your commit graph which are no longer referenced from any branch or tag – every lost commit, including every stash commit you’ve ever created, will be somewhere in that graph.

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/*
  Jenkins ENV Reference:
  env.GIT_COMMIT: the commit sha of the current build
  env.BRANCH_NAME: the branch name OR tag name of the current build, when it exists
  env.GIT_BRANCH: same as BRANCH_NAME
  env.TAG_NAME: the tag name of the current build, when it exists
*/

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Table of Contents

• set -e, -u, -x, -o pipefail
• set -e
• set -x
• set -u
• set -o pipefail
• Setting IFS
• Original Reference

set -e, -u, -x, -o pipefail

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Отправка файлов в Yandex Disk через REST API из Bash

Пример выгрузки файлов на Яндекс.Диск из Bash через официальный REST API.

Подготовка токена для работы с API

Тут все просто.

1. Идем по ссылке и входим под нужной учетной записью Яндекса, после чего нажимаем "Зарегистрировать новое приложение".
2. Настраиваем новое приложение:

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Потоковая репликация PostgreSQL

Потоковая репликация (Streaming Replication) - это репликация, при которой от основного сервера PostgreSQL на реплики передается WAL (Write Ahead Log). И каждая реплика затем по этому журналу изменяет свои данные. Для настройки такой репликации все серверы должны быть одной версии, работать на одной ОС и архитектуре.

Шаги настройки:

1. Настройка master-сервера
2. Настройка доп. сервера (slave)
3. Тестирование репликации

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# Place file in
# /etc/NetworkManager/conf.d/90-disable-randomization.conf
[device-mac-randomization]
# "yes" is the default for scanning in Fedora 25
wifi.scan-rand-mac-address=no

[connection-mac-randomization]
ethernet.cloned-mac-address=random
wifi.cloned-mac-address=random