Code

So, let’s talk about the technologies used in this blog, just for reference. Server The blog is hosted on a DigitalOcean droplet，$5/month，1GB RAM，25GB SSD. I have only used AWS and Digital Ocean before, and apparently, Digital Ocean is the cheaper one. I’ve once also thought about switching to Linode. At that time, DO only got 512MB RAM, so I often run into situations that my programs get killed due to insufficient memory, which was pretty annoying. But just when I was about to pull the trigger, Digital Ocean decided to increase their RAM, so that’s the end of it. ...

You surely have heard HTTP2 and its advantage over the good old HTTP1.1, security, performance blah blah blah… And it bizarrely easy to enable on my Nginx. Firstly some requirements: Nginx > 1.9.5 OpenSSL > 1.0.2 Then add http2 to the server configuration, after listen 443 ssl. server { listen 80; server_name seewang.me www.seewang.me; return 301 https://seewang.me$request_uri; } server { listen 443 ssl http2; server_name seewang.me www.seewang.me; #rest of config... } And that’s it， now we can check it on Chrome Developer Tools > Network tab, we’ll need to right click on the column header and check Protocol column. ...

When I first launched this blog, I set up an SSL certificate from StartCom. It was an okay experience to use, other than I had to renew it via their site every year. But a couple of days ago, Chrome prompted SSL errors when I visited the blog and refused to recognise the certificate even after I renewed it. A quick Google search tells that StartCom got themselves banned by Chrome and Firefox. ...

Internal Command and External Command Internal Command is a part of the Shell program, it consists of some simple Linux system command, which will be recognized by the Shell program and executed within the Shell program. Usually, Shell gets loaded into memory when a Linux system startup. Internal Command is written within bash’s source code, so it run faster than external command as interpreting an internal command does not need to create a new child thread. Some of most common internal command includes exit, history, cd, echo etc. ...