Sometimes we need to modify/add DNS record on Android phone. We can do it on router/PC reliably, but on Android, there is no general reliable way to do that.

There is so much outdated information on the Internet. This answer works for latest QEMU:

Delete email basing on date, or more complex filters.

Some chinese idiots love using non-standard charset. For example, "360 secure archive" is using EUC-CN. They are trying to force everyone to install their shits, but we can crack it.

You might be receiving millions of spamming email. Why it happens and what should I do? This article provides some information.

中国手机号码每天都会收到大量的垃圾短信, 包括商业营销, 政府宣传, 恶意推送赚钱等无意义短信. 分享自己使用的屏蔽方案.

如果你加入了一些Telegram中文群组, 你会遇到大量陌生帐号用中文私聊你, 发送广告.

A solution to use delta airline in-flight WiFi for free, without speed limit. Works for gogoinflight.

If your Synapse is using too much disk space, or your postgresql database is too large. Refer to this guide to clean it up.