杂记 20121008 | Misc Notes 20121008

1. 添加新的MANPATH的正确方法
MANPATH=NEWPATH:$(manpath)

来自 http://ubuntuforums.org/showthread.php?t=1180950

2. 如果DOCTYPE前面有注释，IE9就会进入暴走模式

感谢W3C Validator

3. 删除远端git分支
git push origin :1234

4. 删除远端git标签
git push origin :refs/tags/1234

来自 http://nathanhoad.net/how-to-delete-a-remote-git-tag

1. The correct way to add a new MANPATH:
MANPATH=NEWPATH:$(manpath)

From http://ubuntuforums.org/showthread.php?t=1180950

2. IE9 would go into the quirks mode, if there is any comment before DOCTYPE
Thanks to W3C Validator

3. To remove a remote git branch:
git push origin :1234

4. To remove a remote git tag:
git push origin :refs/tags/1234

From http://nathanhoad.net/how-to-delete-a-remote-git-tag

Comments

Determine Perspective Lines With Off-page Vanishing Point

In perspective drawing, a vanishing point represents a group of parallel lines, in other words, a direction. For any point on the paper, if we want a line towards the same direction (in the 3d space), we simply draw a line through it and the vanishing point. But sometimes the vanishing point is too far away, such that it is outside the paper/canvas. In this example, we have a point P and two perspective lines L1 and L2. The vanishing point VP is naturally the intersection of L1 and L2. The task is to draw a line through P and VP, without having VP on the paper. I am aware of a few traditional solutions: 1. Use extra pieces of paper such that we can extend L1 and L2 until we see VP. 2. Draw everything in a smaller scale, such that we can see both P and VP on the paper. Draw the line and scale everything back. 3. Draw a perspective grid using the Brewer Method. #1 and #2 might be quite practical. #3 may not guarantee a solution, unless we can measure distances/p...

Hardware Password Manager

[Updates 2025-01-20] The original blog post assumes that all passwords are stored in one password manager, and the password manager either unlocks everything or nothing (e.g. Keepass). After discussing with friends, I realized that if I use something like pass , and I use a hardware GPG token, I can actually store and sync all encrypted passwords to all devices, because I will only decrypt the passwords on demand, and the computer will not see the GPG private key. The compromise is that the computer will see the list of all password entries (e.g. accounts), as well as a few other issues . I've been using Keepass for many years. I don't use online password services because I cannot fully trust them. Besides, I may not always have Internet connection, which is why I also don't use a self-hosted service. Everything has been working fine, until I turn my paranoid knob to the max. Here's the thought experiment . The Imaginary Scenario Let's say I have 100 PCs for differe...

ESP32S3: Flash Encryption and Secure Boot

Flash encryption and secure boot are useful security features for ESP32S3 chip. While not perfect, they definitely make it harder to extract the secrets in the chip. However, it is tricky to enable both features at the same time. The topic is actually discussed in the official documentation: ESP32S3 Security Features Security Features Enablement Workflows Especially, the second one mentioned it is recommended to enable flash encryption before secure boot. But I still find the documentation confusing. In the end I was able to successfully enable both, here's my findings. My Understanding After my adventure, here's what I think could have worked. WARNING, this is untested. Follow Security Features Enablement Workflows : Burn all the keys, as long as their purpose eFuses and read/write protections Burn other security eFuses, but DO NOT burn ENABLE_SECURITY_DOWNLOAD in the middle, which is mentined at the end of the instruction for both flash encryption and secure boot. Burn...

WangLu's Notes

Search This Blog