Jake Sylvestre jakesylvestre

To remove a submodule you need to:

Delete the relevant section from the .gitmodules file.
Stage the .gitmodules changes git add .gitmodules
Delete the relevant section from .git/config.
Run git rm --cached path_to_submodule (no trailing slash).
Run rm -rf .git/modules/path_to_submodule (no trailing slash).
Commit git commit -m "Removed submodule "
Delete the now untracked submodule files rm -rf path_to_submodule

Combining two git repositories

Use case: You have repository A with remote location rA, and repository B (which may or may not have remote location rB). You want to do one of two things:

preserve all commits of both repositories, but replace everything from A with the contents of B, and use rA as your remote location
actually combine the two repositories, as if they are two branches that you want to merge, using rA as the remote location

NB: Check out git subtree/git submodule and this Stack Overflow question before going through the steps below. This gist is just a record of how I solved this problem on my own one day.

Before starting, make sure your local and remote repositories are up-to-date with all changes you need. The following steps use the general idea of changing the remote origin and renaming the local master branch of one of the repos in order to combine the two master branches.

Android Emulator

Download Android Studio
Create a virtual device: /Applications/Android\ Studio.app/sdk/tools/android create avd -n <name> -t 1
List your virtual devices: /Applications/Android\ Studio.app/sdk/tools/android list avd
Run your virtual device: /Applications/Android\ Studio.app/sdk/tools/emulator -avd basic

Git Compression of Blobs and Packfiles.

Many users of Git are curious about the lack of delta compression at the object (blob) level when commits are first written. This efficiency is saved until the pack file is written. Loose objects are written in compressed, but non-delta format at the time of each commit.

A simple run though of a commit sequence with only the smallest change to the image (in uncompressed TIFF format to amplify the observable behavior) aids the understanding of this deferred and different approach efficiency.

The command sequence:

Create the repo:

	#
	# Author: Angel Leon (@gubatron)
	# October 2nd 2018
	#
	#
	# README:
	#
	# This CmakeLists.txt file is not meant to produce any executables or libraries.
	#
	# It has been created for CLion or any other cmake compatible IDE users so that they can

	SELECT table,
	formatReadableSize(sum(bytes)) as size,
	min(min_date) as min_date,
	max(max_date) as max_date
	FROM system.parts
	WHERE active
	GROUP BY table

	#include <chrono>
	#include <ctime>
	#include <iostream>

	int main() {

	// std::chrono only
	auto now = std::chrono::system_clock::now();
	std::cout << "std::chrono only: " << std::chrono::duration_cast<std::chrono::seconds>(now.time_since_epoch()).count() << std::endl;

	cmake_minimum_required(VERSION 3.3)
	project(bitcoin)

	set(CMAKE_CXX_STANDARD 11)
	set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")

	add_custom_target(build-bitcoin ALL
	COMMAND ./autogen.sh
	COMMAND ./configure
	COMMAND $(MAKE) WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}

	// SFINAE, enable_if example
	// based on http://stackoverflow.com/questions/257288/is-it-possible-to-write-a-c-template-to-check-for-a-functions-existence


	#include <iostream>
	#include <type_traits>

	class ClassWithToString
	{
	public:

	# taken from http://www.piware.de/2011/01/creating-an-https-server-in-python/
	# generate server.xml with the following command:
	# openssl req -new -x509 -keyout server.pem -out server.pem -days 365 -nodes
	# run as follows:
	# python simple-https-server.py
	# then in your browser, visit:
	# https://localhost:4443

	import BaseHTTPServer, SimpleHTTPServer
	import ssl