vincent zhangw

Opening and closing an SSH tunnel in a shell script the smart way

I recently had the following problem:

From an unattended shell script (called by Jenkins), run a command-line tool that accesses the MySQL database on another host.
That tool doesn't know that the database is on another host, plus the MySQL port on that host is firewalled and not accessible from other machines.

We didn't want to open the MySQL port to the network, but it's possible to SSH from the Jenkins machine to the MySQL machine. So, basically you would do something like

ssh -L 3306:localhost:3306 remotehost

Things to remember when compiling/linking C/C++ software

by Angel Leon. March 17, 2015; August 29, 2019.

Include Paths

On the compilation phase, you will usually need to specify the different include paths so that the interfaces (.h, .hpp) which define structs, classes, constans, and functions can be found.

With gcc and llvm include paths are passed with -I/path/to/includes, you can pass as many -I as you need.

In Windows, cl.exe takes include paths with the following syntax: /I"c:\path\to\includes\ you can also pass as many as you need.

How to Change Open Files Limit on OS X and macOS

This text is the section about OS X Yosemite (which also works for macOS Sierra) from https://docs.basho.com/riak/kv/2.1.4/using/performance/open-files-limit/#mac-os-x

The last time i visited this link it was dead (403), so I cloned it here from the latest snapshot in Archive.org's Wayback Machine https://web.archive.org/web/20170523131633/https://docs.basho.com/riak/kv/2.1.4/using/performance/open-files-limit/

Mac OS X

To check the current limits on your Mac OS X system, run:

Please make fork of this, as this can be removed by Github.com sooner or later.

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	# see https://www.topbug.net/blog/2013/04/14/install-and-use-gnu-command-line-tools-in-mac-os-x/

	# core
	brew install coreutils

	# key commands
	brew install binutils
	brew install diffutils
	brew install ed --default-names
	brew install findutils --with-default-names

	Port: 1080

	1. Create a file /YOUR PATH/gitproxy.sh with content:

	#!/bin/sh
	nc -X 5 -x 127.0.0.1:1080 "$@"

	2. Edit your ~/.gitconfig

	# For git://

	## tsinghua
	cd "$(brew --repo)"
	git remote set-url origin https://mirrors.tuna.tsinghua.edu.cn/git/homebrew/brew.git

	cd "$(brew --repo)/Library/Taps/homebrew/homebrew-core"
	git remote set-url origin https://mirrors.tuna.tsinghua.edu.cn/git/homebrew/homebrew-core.git

	brew update

	# brew bottles

	// if you are allowing 5 requests per second
	final RateLimiter rateLimiter = RateLimiter.create(5.0);
	void throttler() {
	rateLimiter.acquire(); // may wait
	doSomething();
	}

	// if you are allowing 5000 bytes per second
	final RateLimiter rateLimiter = RateLimiter.create(5000.0);
	void submitPacket(byte[] packet) {

	#!/bin/bash
	# bash generate random alphanumeric string
	#

	# bash generate random 32 character alphanumeric string (upper and lowercase) and
	NEW_UUID=$(cat /dev/urandom \| tr -dc 'a-zA-Z0-9' \| fold -w 32 \| head -n 1)

	# bash generate random 32 character alphanumeric string (lowercase only)
	cat /dev/urandom \| tr -dc 'a-zA-Z0-9' \| fold -w 32 \| head -n 1

	git branch -m old_branch new_branch # Rename branch locally
	git push origin :old_branch # Delete the old branch
	git push --set-upstream origin new_branch # Push the new branch, set local branch to track the new remote