okr what’s: objective and key results
key result: 可量化的，具体的
example:
Objective: Enhance my programming skills.
Key Results:
Complete three online courses or tutorials related to new programming languages or frameworks. Build and deploy two personal projects using the learned skills. Read five books or authoritative articles about software development best practices. Contribute to two open-source projects.
user su: what
change user excute a command as another how
-, -l: simulate a full login
-c: excute command
user - group file belong to a group which the owner doesnt belong to
yes: share the data to other groups /public.html owner: root, group: apache,www inspect permission permission list excute permission for directory
read:
read list: ls write: delte/update/add the items(must enter the item first)
excute:
cd read the meta of item: ls -l 1 2 3 4 5 01/01.
Understanding the SSH Encryption and Connection Process
what secure shell: 加密网络协议
algorithm types:
RSA: -b: length 1024 to 8192 bits ED25519: -a: 生成密钥函数的论数，论数越高，加密性越好 1 2 3 4 5 ssh-keygen -t [types] -C comment ssh-keygen -t rsa -b 4096 ssh-keygen -t ed25519 -a 100 the structure
1 2 3 4 5 ssh-ed25519 # types AAAAC3NzaC1lZDI1NTE5AAAAIGZz3nOSfZv3bNtM1x+K5KfBdHJwaYGR0gR7x4HhF6Th user@hostname #pubic key user@host #public key, can change at will comment example:
1 2 alice@workstation alice@workstation-alice.smith@email.com how it work Negotiating: get the session key client: reqeust server: reply public key if first time, the user confirm, add to the known hosts negotiate a session key:TODO authenticate: password: client: public key encrypt, server decrypt ssh key paris: server encrypt data with public key,client decrypt the data with its private key;
what? homebrew command-line
brew update: fetch new version of formula package formula cask: thrid brew tap xx/xx
ASTs - What are they and how to use them
compile step; lexical analysis -> syntax analysis -> code generation
ast tree 1 2 3 4 if (x>y) max =x; else max = y;; abstract tree:
convert code into tree abstract: not save all information, somethings discarded:s
parenthesis; semicolons; else node types:
statement; expression; declaration; 1 2 3 4 type Node interface { Pos() token.Pos // position of first character belonging to the node End() token.
tool compile;; go tool compile;
-m: print optimization; -l: disable inlining;
