hugefiver

File Magic Numbers

Magic numbers are the first bits of a file which uniquely identify the type of file. This makes programming easier because complicated file structures need not be searched in order to identify the file type.

For example, a jpeg file starts with ffd8 ffe0 0010 4a46 4946 0001 0101 0047 ......JFIF.....G ffd8 shows that it's a JPEG file, and ffe0 identify a JFIF type structure. There is an ascii encoding of "JFIF" which comes after a length code, but that is not necessary in order to identify the file. The first 4 bytes do that uniquely.

This gives an ongoing list of file-type magic numbers.

Image Files

hugefiver

Install and Create Emulators using AVDMANAGER and SDKMANAGER

TL;DR

For an emulator that mimics a Pixel 5 Device with Google APIs and ARM architecture (for an M1/M2 Macbook):

1. List All System Images Available for Download: sdkmanager --list | grep system-images

2. Download Image: sdkmanager --install "system-images;android-30;google_atd;arm64-v8a"

hugefiver

// ==UserScript==
// @name                #相亲相爱一嘉人#
// @description         在哔站右下角添加嘉然小姐的live2d模型
// @version             1.0.1
// @namespace           https://github.com/journey-ad
// @author              journey-ad
// @include             /^https:\/\/(www|live|space|t)\.bilibili\.com\/.*$/
// @icon                https://www.google.com/s2/favicons?domain=bilibili.com
// @license             GPL v2
// @run-at              document-end

hugefiver

set_proxy() {
        export hostip=$(cat /etc/resolv.conf | grep nameserver | awk '{ print $2 }')
        local proxy_url="http://${hostip}:7890"
        export https_proxy="$proxy_url"
        export http_proxy="$proxy_url"
        export all_proxy="$proxy_url"
}

unset_proxy() {
        export https_proxy="" http_proxy="" all_proxy=""

hugefiver

This downloads standalone 64-bit MSVC compiler, linker & other tools, also headers/libraries from Windows SDK into portable folder, without installing Visual Studio. Has bare minimum components - no UWP/Store/WindowsRT stuff, just files & tools for 64-bit native desktop app development.

Run python.exe portable-msvc.py and it will download output into msvc folder. By default it will download latest available MSVC & Windows SDK - currently v14.32.17.2 and v10.0.22621.0.

You can list available versions with python.exe portable-msvc.py --show-versions and then pass versions you want with --msvc-version and --sdk-version arguments.

To use cl.exe/link.exe from output folder, first run setup.bat - after that PATH/INCLUDE/LIB env variables will be setup to use all the tools as usual. You can also use clang-cl.exe with these includes & libraries.

To use clang-cl.exe without running setup.bat, pass extra /winsysroot msvc argument (msvc is folder name where output is stored).

hugefiver

# Install autocomplete
#Install-Module PSReadLine

# install PSReadLine
#Install-Module -Name PSReadLine

# autocomplete
Import-Module PSReadLine
Set-PSReadLineOption -PredictionSource History

hugefiver

# machine
$path = [Environment]::GetEnvironmentVariable('ENV_NAME', 'Machine')
[Environment]::SetEnvironmentVariable("ENV_NAME", $newpath, 'Machine')

# user
$path = [Environment]::GetEnvironmentVariable('ENV_NAME', 'User')
[Environment]::SetEnvironmentVariable("ENV_NAME", $newpath, 'USer')

hugefiver

# generate a key pair
gpg --gen-key
# , with choices
gpg --full-gen-key # or `--full-generate-key`
# , need more choice, such as ecc key pair
gpg --full-gen-key --expert

# list keys
gpg --list-keys # ,or shorter `-k`
# , or secret key

hugefiver

; A small self applicable scheme->llvm compiler.
;; ,  Tobias Nurmiranta
;;
;; -- To Use It --
;; Reads scheme-code from standard input.
;; cat code.ss|mzscheme --script compile.ss|llvm-as -f -o=test.bc;lli test.bc
;;
;; The compiler is painfully slow since it for testing purposes
;; compiles all help functions as well (see variable bootstrap). 
;; It extends standard scheme with a subset of available

hugefiver

(require lazy)

(((λ (f) ((λ (x) (f (x x))) (λ (x) (f (x x))))) (λ (f) (λ (n) (if (> n 0) (string-append "别老惦记着你那破" (f (- n 1)) "了") "")))) 10)