dawn fafucoder

常用的几个 Ruby 版本管理工具有：rvm，rbenv，ry，rbfu。rvm 应该是最早出现、使用最多的，因为过于强大以至于违背了某个 Linux 软件开发原则，所以出现了很多轻便的替代者，其中来自 37signals 的 rbenv 就很受欢迎。ry 和 rbfu 看上去更轻便，不过使用不广泛。之前使用过rvm, 这次尝试下rbenv。

我的环境是 Ubuntu14.04

1. 安装 rbenv

rbenv的源代码托管在github，在终端中，从 github 上将 rbenv 源码 clone 到本地，然后设置 $PATH。

git clone git://github.com/sstephenson/rbenv.git ~/.rbenv
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' &gt;&gt; ~/.bashrc

Colours in terminal

It's a common confusion about terminal colours... Actually we have this:

plain ascii
ansi escape codes (16 colour codes with bold/italic and background)
256 colour palette (216 colours + 16 ansi + 24 gray) (colors are 24bit)
24bit true colour ("888" colours (aka 16 milion))

printf "\x1b[${bg};2;${red};${green};${blue}m\n"

	package main

	import (
	"fmt"
	"go/ast"
	"go/parser"
	"go/printer"
	"go/token"
	"log"
	"os"

	dawn@node-3:~$ kubectl ko trace kube-system/kube-ovn-pinger-4tm8h 192.168.101.1 icmp
	+ kubectl exec ovn-central-7c95745dc4-v8rb5 -n kube-system -- ovn-trace --ct=new ovn-default 'inport == "kube-ovn-pinger-4tm8h.kube-system" && ip.ttl == 64 && icmp && eth.src == 00:00:00:17:34:1A && ip4.src == 10.19.0.5 && eth.dst == 00:00:00:F9:34:7E && ip4.dst == 192.168.101.1'
	# icmp,reg14=0x5,vlan_tci=0x0000,dl_src=00:00:00:17:34:1a,dl_dst=00:00:00:f9:34:7e,nw_src=10.19.0.5,nw_dst=192.168.101.1,nw_tos=0,nw_ecn=0,nw_ttl=64,icmp_type=0,icmp_code=0

	ingress(dp="ovn-default", inport="kube-ovn-pinger-4tm8h.kube-system")
	---------------------------------------------------------------------
	0. ls_in_port_sec_l2 (ovn-northd.c:4520): inport == "kube-ovn-pinger-4tm8h.kube-system" && eth.src == {00:00:00:17:34:1a}, priority 50, uuid d80aa01b
	next;
	1. ls_in_port_sec_ip (ovn-northd.c:4188): inport == "kube-ovn-pinger-4tm8h.kube-system" && eth.src == 00:00:00:17:34:1a && ip4.src == {10.19.0.5}, priority 90, uuid 04b1a887
	next