### Quick Setup: Onboard and Install Service

Source: https://github.com/fechin/reference/blob/main/source/_posts/openclaw.md

Command to onboard and install the OpenClaw service.

```bash
openclaw onboard --install-daemon
```

--------------------------------

### Quick Setup: Install OpenClaw

Source: https://github.com/fechin/reference/blob/main/source/_posts/openclaw.md

Instructions for installing OpenClaw using curl or npm.

```bash
# macOS / Linux / WSL2
curl -fsSL https://openclaw.ai/install.sh | bash
# or via npm
npm install -g openclaw@latest
```

--------------------------------

### Worktree Configuration Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/cursor-cli.md

Example JSON configuration for worktree setup scripts.

```json
{
  "setup": ["npm install", "cp .env.example .env"]
}
```

--------------------------------

### Getting started

Source: https://github.com/fechin/reference/blob/main/source/_posts/regex.md

Import the regular expressions module in Python.

```python
import re
```

--------------------------------

### CDN Setup

Source: https://github.com/fechin/reference/blob/main/source/_posts/vue.md

Quick start setup using a CDN link for Vue.js.

```html
<script src="https://unpkg.com/vue@3"></script>
<div id="app">{{ message }}</div>
<script>
  Vue.createApp({
    data() {
      return { message: "Hello Vue!" };
    }
  }).mount("#app");
</script>
```

--------------------------------

### Basic Usage

Source: https://github.com/fechin/reference/blob/main/source/_posts/opencode.md

Examples of starting the TUI, running non-interactively, continuing sessions, and piping input.

```bash
# Start TUI for current directory
$ opencode

# Start TUI for a specific project
$ opencode /path/to/project

# Run non-interactively (headless)
$ opencode run "Explain how closures work in JS"

# Continue last session
$ opencode run -c "Fix the failing tests"

# Pipe input into opencode
$ cat error.log | opencode run "Explain this error"
```

--------------------------------

### Start a new Django Project

Source: https://github.com/fechin/reference/blob/main/source/_posts/django.md

Commands to create a new Django project, including setting up a virtual environment, installing Django, creating the project structure, and starting a new app.

```bash
# Create et access project folder
~$  mkdir project_name
~$  cd project_name

# Create Python virtual env
~$  python3 -m venv venv

# Activate virtual env
~$  source venv/bin/activate

# If you want to deactivate virtual env
~$  deactivate

# Install django (~= same as 4.2.*)
~$  pip install django~=4.2.0

# New django project (from project_name folder)
~$  django-admin startproject config

# Create app (from project_name folder)
~$  python manage.py startapp app_name
```

--------------------------------

### Server & Remote Commands

Source: https://github.com/fechin/reference/blob/main/source/_posts/opencode.md

Examples for starting the OpenCode headless API server, web UI server, enabling mDNS discovery, and setting up basic authentication.

```bash
# Headless API server
$ opencode serve --port 4096

# Web UI server
$ opencode web --port 4096 --hostname 0.0.0.0

# Enable mDNS discovery
$ opencode serve --mdns

# Enable basic auth
$ OPENCODE_SERVER_PASSWORD=secret opencode serve
```

--------------------------------

### Install Script

Source: https://github.com/fechin/reference/blob/main/source/_posts/opencode.md

Recommended installation method using a script.

```bash
$ curl -fsSL https://opencode.ai/install | bash
```

--------------------------------

### Start a Dev Server

Source: https://github.com/fechin/reference/blob/main/source/_posts/quickref.md

Start the development server.

```shell
$ npm run dev
```

--------------------------------

### Quick Start

Source: https://github.com/fechin/reference/blob/main/source/_posts/gemini-cli.md

Install Gemini CLI globally, via Homebrew, or run without installing. Launch interactive or non-interactive sessions, pipe content, resume sessions.

```bash
# Install globally
$ npm install -g @google/gemini-cli

# Or via Homebrew
$ brew install gemini-cli

# Or run without installing
$ npx @google/gemini-cli

# Launch interactive session
$ gemini

# Non-interactive (headless)
$ gemini -p "summarize README.md"

# Pipe content to Gemini
$ cat logs.txt | gemini -p "find errors"

# Run prompt and continue interactively
$ gemini -i "explain this project"

# Resume most recent session
$ gemini -r latest

# Resume with new prompt
$ gemini -r latest "check for type errors"
```

--------------------------------

### Install via Homebrew

Source: https://github.com/fechin/reference/blob/main/source/_posts/opencode.md

Installation for macOS/Linux using Homebrew.

```bash
$ brew install anomalyco/tap/opencode
```

--------------------------------

### Install Homebrew

Source: https://github.com/fechin/reference/blob/main/source/_posts/homebrew.md

Installs Homebrew by downloading and executing the official installation script.

```bash
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
```

--------------------------------

### Install via Node.js

Source: https://github.com/fechin/reference/blob/main/source/_posts/opencode.md

Installation using npm.

```bash
$ npm install -g opencode-ai
```

--------------------------------

### Option examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/grep.md

Use regex _(lines starting with 'al')_

```shell
grep -e '^al' filename
```

--------------------------------

### Start and enable PostgreSQL

Source: https://github.com/fechin/reference/blob/main/source/_posts/django.md

Starts the PostgreSQL service and enables it to start automatically at boot.

```bash
sudo systemctl start postgresql
sudo systemctl enable postgresql
```

--------------------------------

### Wildcard Examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/find.md

Examples of using wildcards with the -name option to find files.

```shell
$ find . -name "*.txt"
```

```shell
$ find . -name "2020*.csv"
```

```shell
$ find . -name "json_*"
```

--------------------------------

### Testing Setup

Source: https://github.com/fechin/reference/blob/main/source/_posts/vue.md

Commands to install Vitest and Vue Test Utils.

```bash
npm install vitest @vue/test-utils
```

--------------------------------

### Quick Start Commands

Source: https://github.com/fechin/reference/blob/main/source/_posts/grok-cli.md

Commands for running Grok CLI immediately, installing it globally, starting an interactive session, sending initial messages, using headless mode, specifying a model, setting a working directory, and setting the maximum number of tool rounds.

```bash
# Run immediately (no install)
$ GROK_API_KEY=your_key npx -y grok-cli-hurry-mode@latest

# Install globally
$ npm install -g grok-cli-hurry-mode@latest

# Start interactive session
$ grok

# Send initial message
$ grok "Help me understand this project"

# Headless / non-interactive mode
$ grok -p "explain the auth module"

# Use a specific model
$ grok -m grok-4-latest "refactor this file"

# Set working directory
$ grok -d /path/to/project

# Set max tool rounds
$ grok --max-tool-rounds 100 "rewrite the API"
```

--------------------------------

### grid-row-start & grid-row-end Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/css3.md

Example of setting grid-row-start and grid-row-end properties.

```css
grid-row-start: 2;
grid-row-end: span 2;
```

--------------------------------

### Alternative Install from Source

Source: https://github.com/fechin/reference/blob/main/source/_posts/openclaw.md

Instructions for installing OpenClaw from its source code.

```bash
# From source
git clone https://github.com/openclaw/openclaw.git
cd openclaw && pnpm install && pnpm build
pnpm link --global
```

--------------------------------

### Install via Chocolatey/Scoop

Source: https://github.com/fechin/reference/blob/main/source/_posts/opencode.md

Installation for Windows using Chocolatey or Scoop.

```bash
choco install opencode      # Chocolatey
scoop install opencode      # Scoop
```

--------------------------------

### Router GET Method Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/express.md

An example of handling GET requests for a specific route within a router.

```javascript
//depends on where the router "use()"
router.get('/events', (req, res, next) => {
  //..
});
```

--------------------------------

### Initial Project Setup Commands

Source: https://github.com/fechin/reference/blob/main/source/_posts/django.md

Commands to migrate the database, create a superuser, and collect static files.

```bash
(myprojectenv)$ ~/myprojectdir/manage.py makemigrations
(myprojectenv)$ ~/myprojectdir/manage.py migrate
```

```bash
(myprojectenv)$ ~/myprojectdir/manage.py createsuperuser
```

```bash
(myprojectenv)$ ~/myprojectdir/manage.py collectstatic
```

--------------------------------

### Installation

Source: https://github.com/fechin/reference/blob/main/source/_posts/symfony.md

Installs the Symfony CLI.

```bash
curl -sS https://get.symfony.com/cli/installer | bash
```

--------------------------------

### Development Setup

Source: https://github.com/fechin/reference/blob/main/README.md

Steps to set up the development environment for the Reference project.

```bash
git clone https://github.com/Fechin/reference.git
npm install
npm run dev
```

--------------------------------

### Start server

Source: https://github.com/fechin/reference/blob/main/source/_posts/django.md

Command to start the Django development server.

```bash
~$  python manage.py runserver  => ex.  http://127.0.0.1:8000
```

--------------------------------

### Hello World

Source: https://github.com/fechin/reference/blob/main/source/_posts/cursor-cli.md

Examples of interactive agent sessions and one-shot prompts.

```bash
# Interactive agent session
$ agent

# One-shot prompt (print mode)
$ agent -p "List all TODO comments in this repo"

# Ask a question (read-only)
$ agent --mode=ask "How does auth work here?"

# Plan only (no edits)
$ agent --plan "Refactor the payment module"
```

--------------------------------

### REGEXP_INSTR Function Examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/regex.md

Examples showcasing the REGEXP_INSTR function to find the starting position of a substring matching a regular expression.

```sql
mysql> SELECT regexp_instr('aa aaa aaaa', 'a{3}');
2
mysql> SELECT regexp_instr('abba', 'b{2}', 2);
2
mysql> SELECT regexp_instr('abbabba', 'b{2}', 1, 2);
5
mysql> SELECT regexp_instr('abbabba', 'b{2}', 1, 3, 1);
7
```

--------------------------------

### Curl GET/HEAD Examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/curl.md

Examples of using Curl for GET and HEAD requests, including verbose output and proxy settings.

```bash
curl -I https://cheatsheets.zip                                     # `curl` sends a request
curl -v -I https://cheatsheets.zip                                  # `curl` request with details
curl -X GET https://cheatsheets.zip                                # use explicit http method for `curl`
curl --noproxy 127.0.0.1 http://www.stackoverflow.com               # `curl` without http proxy
curl --connect-timeout 10 -I -k https://cheatsheets.zip           # `curl` has no timeout by default
curl --verbose --header "Host: www.mytest.com:8182" cheatsheets.zip # `curl` get extra header
curl -k -v https://www.google.com                                   # `curl` get response with headers
```

--------------------------------

### Go Client and Server Setup

Source: https://github.com/fechin/reference/blob/main/source/_posts/socket-io.md

Sets up a Socket.IO client connection and a basic Go server.

```go
import "github.com/googollee/go-socket.io-client"
socket, err := gosocketio.Dial(
    gosocketio.GetUrl("localhost", 3000, false),
    transport.GetDefaultWebsocketTransport(),
)
```

```go
import (
    "github.com/googollee/go-socket.io"
    "net/http"
)

server, _ := socketio.NewServer(nil)
server.OnConnect("/", func(s socketio.Conn) error {
    fmt.Println("Client connected:", s.ID())
    return nil
})
http.Handle("/socket.io/", server)
go http.ListenAndServe(":3000", nil)
```

--------------------------------

### HVALS Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Get all the values in a hash

```shell script
redis> HSET myhash field1 "Hello"
(integer) 1
redis> HSET myhash field2 "World"
(integer) 1
redis> HVALS myhash
1) "Hello"
2) "World"
```

--------------------------------

### Go Installation

Source: https://github.com/fechin/reference/blob/main/source/_posts/socket-io.md

Installs the Socket.IO client library for Go.

```bash
go get github.com/googollee/go-socket.io
```

--------------------------------

### HKEYS Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Get all the fields in a hash

```shell script
redis> HSET myhash field1 "Hello"
(integer) 1
redis> HSET myhash field2 "World"
(integer) 1
redis> HKEYS myhash
1) "field1"
2) "field2"
```

--------------------------------

### LLEN Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Get the length of a list.

```shell script
redis> LPUSH mylist "World"
(integer) 1
redis> LPUSH mylist "Hello"
(integer) 2
redis> LLEN mylist
(integer) 2
```

--------------------------------

### opencode.json configuration example

Source: https://github.com/fechin/reference/blob/main/source/_posts/opencode.md

Example of the main opencode.json configuration file.

```json
{
  "$schema": "https://opencode.ai/config.json",
  "model": "anthropic/claude-sonnet-4-5",
  "small_model": "anthropic/claude-haiku-4-5",
  "default_agent": "build",
  "autoupdate": true,
  "snapshot": true,
  "share": "manual",
  "instructions": ["AGENTS.md", "docs/*.md"],
  "provider": {
    "anthropic": {
      "options": { "timeout": 600000 }
    }
  },
  "permission": {
    "edit": "ask",
    "bash": "ask"
  },
  "compaction": {
    "auto": true,
    "prune": true,
    "reserved": 10000
  },
  "server": {
    "port": 4096,
    "mdns": true
  },
  "tools": {
    "write": false,
    "bash": false
  },
  "disabled_providers": ["openai"],
  "enabled_providers": ["anthropic"]
}
```

--------------------------------

### SMEMBERS Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Get all the members in a set.

```shell script
redis> SADD myset "Hello"
(integer) 1
redis> SADD myset "World"
(integer) 1
redis> SMEMBERS myset
1)
"Hello"
2)
"World"
```

--------------------------------

### GET Command Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Retrieves the value of a key.

```shell
redis> GET nonexisting
(nil)
redis> SET mykey "Hello"
"OK"
redis> GET mykey
"Hello"

```

--------------------------------

### Dofile and Loadfile Examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/lua.md

Shows how to execute Lua files immediately with dofile and load them for later execution with loadfile.

```lua
-- Using dofile
dofile("my_file.lua") -- Executes my_file.lua immediately

-- Using loadfile
local my_func = loadfile("my_file.lua")
if my_func then
  -- my_file.lua is valid, now execute it
  my_func()
else
  print("Error loading file.")
end
```

--------------------------------

### Config sample

Source: https://github.com/fechin/reference/blob/main/source/_posts/ssh.md

Launch by alias

```shell
$ ssh server1
```

--------------------------------

### Programming - Create regex to match all words that start with "ban"

Source: https://github.com/fechin/reference/blob/main/source/_posts/chatgpt.md

Example prompt for creating a regex to match words starting with 'ban'.

```text
Create regex to match all words that start with "ban"
```

--------------------------------

### Starting a Server

Source: https://github.com/fechin/reference/blob/main/source/_posts/express.md

Demonstrates how to start an Express.js server on port 3000.

```javascript
var express = require('express');

var app = express();
app.listen(3000);
```

--------------------------------

### Start an app

Source: https://github.com/fechin/reference/blob/main/source/_posts/pm2.md

Start, daemonize, and monitor an application using PM2.

```shell
$ pm2 start app.js
```

```shell
$ pm2 start bashscript.sh
```

```shell
$ pm2 start python-app.py --watch
```

```shell
$ pm2 start binary-file -- --port 1520
```

--------------------------------

### COMMAND Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Get array of Redis command details

```shell
redis> COMMAND
1) 1) "georadius_ro"
     2) (integer) -6
     3) 1) "readonly"
        2) "movablekeys"
     4) (integer) 1
     5) (integer) 1
     6) (integer) 1
     7) 1) "@read"
        2) "@geo"
        3) "@slow"
  2) 1) "zpopmin"
     2) (integer) -2
     3) 1) "write"
        2) "fast"
  ........
```

--------------------------------

### HLEN Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Get the number of fields in a hash

```shell script
redis> HSET myhash field1 "Hello"
(integer) 1
redis> HSET myhash field2 "World"
(integer) 1
redis> HLEN myhash
(integer) 2
```

--------------------------------

### Rust Client Setup

Source: https://github.com/fechin/reference/blob/main/source/_posts/socket-io.md

Sets up a Socket.IO client connection for Rust.

```rust
use socketio_client::ClientBuilder;

async fn run() -> Result<(), Box<dyn std::error::Error>> {
    let socket = ClientBuilder::new("http://localhost:3000")
        .transport("websocket")
        .connect()
        .await?;
    Ok(())
}
```

--------------------------------

### HGETALL Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Get all the fields and values in a hash

```shell script
redis> HSET myhash field1 "Hello"
(integer) 1
redis> HSET myhash field2 "World"
(integer) 1
redis> HGETALL myhash
1) "field1"
2) "Hello"
3) "field2"
4) "World"
```

--------------------------------

### HGET Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Get the value of a hash field

```shell script
redis> HSET myhash field1 "foo"
(integer) 1
redis> HGET myhash field1
"foo"
redis> HGET myhash field2
(nil)
```

--------------------------------

### hello.go

Source: https://github.com/fechin/reference/blob/main/source/_posts/go.md

A simple "Hello, world!" program in Go.

```go
package main

import "fmt"

func main() {
    fmt.Println("Hello, world!")
}
```

--------------------------------

### Symbol Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/ruby.md

A basic example of creating a Hash with Symbol keys.

```ruby
week_days = {sunday: 11, monday: 222}
```

--------------------------------

### LINDEX Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Get an element from a list by its index.

```shell script
redis> LPUSH mylist "World"
(integer) 1
redis> LPUSH mylist "Hello"
(integer) 2
redis> LINDEX mylist 0
"Hello"
redis> LINDEX mylist -1
"World"
redis> LINDEX mylist 3
(nil)
```

--------------------------------

### ZCARD Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Get the number of members in a sorted set

```shell script
redis> ZADD myzset 1 "one"
(integer) 1
redis> ZADD myzset 2 "two"
(integer) 1
redis> ZCARD myzset
(integer) 2
```

--------------------------------

### Plan Mode Examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/cursor-cli.md

Examples of using the agent in plan mode for read-only analysis.

```bash
$ agent --plan
$ agent --mode=plan "Refactor auth"
```

--------------------------------

### HSTRLEN Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Get the length of the value of a hash field

```shell script
redis> HMSET myhash f1 HelloWorld f2 99 f3 -256
"OK"
redis> HSTRLEN myhash f1
(integer) 10
redis> HSTRLEN myhash f2
(integer) 2
redis> HSTRLEN myhash f3
(integer) 4
```

--------------------------------

### init function execution order

Source: https://github.com/fechin/reference/blob/main/source/_posts/go.md

Demonstrates the execution order of var, const, and init functions.

```go
var num = setNumber()

func setNumber() int {
    return 42
}
func init() {
    num = 0
}
func main() {
    fmt.Println(num) // => 0
}
```

--------------------------------

### HMGET Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Get the values of all the given hash fields

```shell script
redis> HSET myhash field1 "Hello"
(integer) 1
redis> HSET myhash field2 "World"
(integer) 1
redis> HMGET myhash field1 field2 nofield
1) "Hello"
2) "World"
3) (nil)
```

--------------------------------

### Install via Docker

Source: https://github.com/fechin/reference/blob/main/source/_posts/opencode.md

Running OpenCode using Docker.

```bash
$ docker run -it --rm ghcr.io/anomalyco/opencode
```

--------------------------------

### Overlap and Spacing Examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/latex.md

Examples demonstrating overlap and spacing control in KaTeX.

```KaTeX
{=}\mathllap{/\,}
```

```KaTeX
\left(x^{\smash{2}}\right)
```

```KaTeX
\mathrlap{\,/}{=}
```

```KaTeX
\sqrt{\smash[b]{y}}
```

```KaTeX
\sum_{\mathclap{1\le i\le j\le n}} x_{ij}
```

--------------------------------

### SET and GET Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Sets a key-value pair and retrieves its value.

```shell
redis> SET mykey "Hello world"
OK
redis> GET mykey
"Hello world"

```

--------------------------------

### Awk Program Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/awk.md

An example Awk program that prints a start message, then prints records that do not contain 'login' or 'shutdown', and finally prints an end message.

```awk
awk '
    BEGIN { print "\n>>>Start" }
    !/(login|shutdown)/ { print NR, $0 }
    END { print "<<<END\n" }
' /etc/passwd
```

--------------------------------

### Basic Netcat Usage

Source: https://github.com/fechin/reference/blob/main/source/_posts/nc.md

Demonstrates the fundamental commands for connecting to a host and listening for incoming connections using Netcat.

```shell
$ nc [options] [host] [port]
```

```shell
$ nc -lp port [host] [port]
```

--------------------------------

### JavaScript Client and Server Setup

Source: https://github.com/fechin/reference/blob/main/source/_posts/socket-io.md

Sets up a Socket.IO client connection to a server and a basic Node.js server.

```javascript
import { io } from 'socket.io-client';
const socket = io('http://localhost:3000');
```

```javascript
const io = require('socket.io')(3000, {
  cors: { origin: '*' }
});
io.on('connection', (socket) => {
  console.log('Client connected:', socket.id);
});
```

--------------------------------

### Map Initialization and Operations

Source: https://github.com/fechin/reference/blob/main/source/_posts/go.md

Demonstrates creating, accessing, updating, deleting, and checking for keys in a map.

```go
m := make(map[string]int)
m["k1"] = 7
m["k2"] = 13
fmt.Println(m) // => map[k1:7 k2:13]

v1 := m["k1"]
fmt.Println(v1)     // => 7
fmt.Println(len(m)) // => 2

delete(m, "k2")
fmt.Println(m) // => map[k1:7]

_, prs := m["k2"]
fmt.Println(prs) // => false

n := map[string]int{"foo": 1, "bar": 2}
fmt.Println(n) // => map[bar:2 foo:1]
```

--------------------------------

### Single line comments

Source: https://github.com/fechin/reference/blob/main/source/_posts/python.md

Example of a single-line comment in Python, starting with a hash symbol.

```python
# This is a single line comments.
```

--------------------------------

### Docker Support

Source: https://github.com/fechin/reference/blob/main/source/_posts/alpine-linux.md

Commands for installing, starting, and enabling Docker service.

```bash
# Install Docker
apk add docker

# Start Docker service
rc-service docker start

# Enable Docker at boot
rc-update add docker default
```

--------------------------------

### Ask Mode Examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/cursor-cli.md

Examples of using the agent in ask mode for question and answer interactions.

```bash
$ agent --mode=ask
$ agent --mode=ask "How does caching work?"
```

--------------------------------

### TTL Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Demonstrates getting the time to live for a key using TTL.

```shell
redis> SET mykey "Hello"
"OK"
redis> EXPIRE mykey 10
(integer) 1
redis> TTL mykey
(integer) 10
```

--------------------------------

### Installing with Homebrew

Source: https://github.com/fechin/reference/blob/main/source/_posts/hook.md

Commands to install the Hook interpreter using Homebrew.

```text
brew tap hook-lang/hook
brew install hook
hook --help
```

--------------------------------

### ZMSCORE Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Get the score associated with the given members in a sorted set.

```shell
redis> ZADD myzset 1 "one"
(integer) 1
redis> ZADD myzset 2 "two"
(integer) 1
redis> ZMSCORE myzset "one" "two" "nofield"
1) "1"
2) "2"
3) (nil)
```

--------------------------------

### SRANDMEMBER Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Get one or multiple random members from a set.

```shell script
redis> SADD myset one two three
(integer) 3
redis> SRANDMEMBER myset
"three"
redis> SRANDMEMBER myset 2
1)
"two"
2)
"three"
redis> SRANDMEMBER myset -5
1)
"one"
2)
"two"
3)
"three"
4)
"three"
5)
"one"
```

--------------------------------

### Java Client and Server Setup

Source: https://github.com/fechin/reference/blob/main/source/_posts/socket-io.md

Sets up a Socket.IO client connection and a basic Java server.

```java
IO.Options opts = new IO.Options();
Socket socket = IO.socket("http://localhost:3000", opts);
socket.connect();
```

```java
import io.socket.engineio.server.EngineIoServer;
import io.socket.server.SocketIoServer;

EngineIoServer engineIo = new EngineIoServer();
SocketIoServer io = new SocketIoServer(engineIo);
io.listen(3000);

io.on("connection", args -> {
    var client = args[0];
    System.out.println("Client connected: " + client.id());
});
```

--------------------------------

### Struct Literals

Source: https://github.com/fechin/reference/blob/main/source/_posts/go.md

Examples of different ways to initialize struct literals.

```go
v := Vertex{X: 1, Y: 2}
// Field names can be omitted
v := Vertex{1, 2}
// Y is implicit
v := Vertex{X: 1}
```

--------------------------------

### Namespaces - Server (All Languages)

Source: https://github.com/fechin/reference/blob/main/source/_posts/socket-io.md

Example of handling connections to a specific namespace on the server.

```javascript
io.of('/admin').on('connection', (socket) => {
  console.log('Admin connected:', socket.id);
});
```

```go
server.Of("/admin").OnConnect(func(s socketio.Conn) {
  fmt.Println("Admin connected:", s.ID())
})
```

--------------------------------

### PTTL Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Shows how to get the time to live for a key in milliseconds using PTTL.

```shell
redis> SET mykey "Hello"
"OK"
redis> EXPIRE mykey 1
(integer) 1
redis> PTTL mykey
(integer) 1000
```

--------------------------------

### Worktree Creation Examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/cursor-cli.md

Examples of creating worktrees, including auto-named, named, and from specific branches.

```bash
# Auto-named worktree
$ agent -w

# Named worktree
$ agent -w feature-auth

# Worktree from specific branch
$ agent -w fix --worktree-base main

# Skip setup scripts
$ agent -w feature --skip-worktree-setup
```

--------------------------------

### RPOP Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Demonstrates removing and getting the last element from a list using RPOP.

```shell
redis> RPUSH mylist "one"
(integer) 1
redis> RPUSH mylist "two"
(integer) 2
redis> RPUSH mylist "three"
(integer) 3
redis> RPOP mylist
"three"
redis> LRANGE mylist 0 -1
1) "one"
2) "two"
```

--------------------------------

### Setup and Loop

Source: https://github.com/fechin/reference/blob/main/source/_posts/arduino-programming.md

The basic structure of an Arduino sketch includes the setup() function, which runs once, and the loop() function, which runs repeatedly.

```cpp
void setup() {
  // Code here runs once
}

void loop() {
  // Code here runs repeatedly
}
```

--------------------------------

### LPOP Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Remove and get the first element in a list, or block until one is available.

```shell script
LPOP key [count]
```

--------------------------------

### hello.c

Source: https://github.com/fechin/reference/blob/main/source/_posts/c.md

Basic Hello World program in C.

```c
#include <stdio.h>

int main(void) {
  printf("Hello World!\n");

  return 0;
}

```

--------------------------------

### BRPOP Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Remove and get the last element in a list, or block until one is available.

```shell script
redis> DEL list1 list2
(integer) 0
redis> RPUSH list1 a b c
(integer) 3
redis> BRPOP list1 list2 0
1)
"list1"
2)
"c"
```

--------------------------------

### fmt.Printf

Source: https://github.com/fechin/reference/blob/main/source/_posts/go.md

Demonstrates various formatting verbs with fmt.Printf and fmt.Sprintf.

```go
package main

import (
	"fmt"
	"os"
)

type point struct {
	x, y int
}

func main() {
	p := point{1, 2}
	fmt.Printf("%v\n", p)                        // => {1 2}
	fmt.Printf("%+v\n", p)                       // => {x:1 y:2}
	fmt.Printf("%#v\n", p)                       // => main.point{x:1, y:2}
	fmt.Printf("%T\n", p)                        // => main.point
	fmt.Printf("%t\n", true)                     // => TRUE
	fmt.Printf("%d\n", 123)                      // => 123
	fmt.Printf("%b\n", 14)                       // => 1110
	fmt.Printf("%c\n", 33)                       // => !
	fmt.Printf("%x\n", 456)                      // => 1c8
	fmt.Printf("%f\n", 78.9)                     // => 78.9
	fmt.Printf("%e\n", 123400000.0)              // => 1.23E+08
	fmt.Printf("%E\n", 123400000.0)              // => 1.23E+08
	fmt.Printf("%s\n", "\"string\"")             // => "string"
	fmt.Printf("%q\n", "\"string\"")             // => "\"string\""
	fmt.Printf("%x\n", "hex this")               // => 6.86578E+15
	fmt.Printf("%p\n", &p)                       // => 0xc00002c040
	fmt.Printf("|%6d|%6d|\n", 12, 345)           // => |    12|   345|
	fmt.Printf("|%6.2f|%6.2f|\n", 1.2, 3.45)     // => |  1.20|  3.45|
	fmt.Printf("|%-6.2f|%-6.2f|\n", 1.2, 3.45)   // => |1.20  |3.45  |
	fmt.Printf("|%6s|%6s|\n", "foo", "b")        // => |   foo|     b|
	fmt.Printf("|%-6s|%-6s|\n", "foo", "b")      // => |foo   |b     |

	s := fmt.Sprintf("a %s", "string")
	fmt.Println(s)

	fmt.Fprintf(os.Stderr, "an %s\n", "error")
}

```

--------------------------------

### BLPOP Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Remove and get the first element in a list, or block until one is available.

```shell script
redis> DEL list1 list2
(integer) 0
redis> RPUSH list1 a b c
(integer) 3
redis> BLPOP list1 list2 0
1)
"list1"
2)
"a"
```

--------------------------------

### Current date and time

Source: https://github.com/fechin/reference/blob/main/source/_posts/php.md

Example of getting the current date and time using the DateTime object in PHP.

```php
// DateTime in PHP handles both date and time

<?php
$now = new DateTime();
echo $now->format('Y-m-d H:i:s.u'); 

// Output ex: 2024-04-27 14:35:22.123456
```

--------------------------------

### Gateway: Startup Options

Source: https://github.com/fechin/reference/blob/main/source/_posts/openclaw.md

Various options for running the OpenClaw gateway.

```bash
openclaw gateway run             # foreground
openclaw gateway run --port 19001
openclaw gateway run --force     # kill existing listener
openclaw gateway run --verbose   # verbose to stdout
openclaw gateway run --bind lan  # bind to LAN
openclaw gateway run --auth token --token <t>
```

--------------------------------

### Registry Management

Source: https://github.com/fechin/reference/blob/main/source/_posts/powershell.md

Examples for managing registry keys and values, including getting, setting, creating, and removing them.

```powershell
# Retrieve registry key values
Get-ItemProperty -Path "HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\*" | Select DisplayName, DisplayVersion

# Set registry key values
Set-ItemProperty -Path "HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\*" -Name "SettingName" -Value "NewValue"

# Create a new registry key value
New-ItemProperty -Path "HKCU:\Software\MyApp" -Name "NewSetting" -Value "NewValue" -PropertyType String

# Remove a registry key value
Remove-ItemProperty -Path "HKCU:\Software\MyApp" -Name "SettingToRemove"

# Check if a registry key exists
Test-Path "HKLM:\Software\MyApp"
```

--------------------------------

### Option examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/grep.md

Print the name of the file(s) of matches

```shell
grep -l 'robot' /var/log/*
```

--------------------------------

### Running Perl from Command Line

Source: https://github.com/fechin/reference/blob/main/source/_posts/perl.md

Examples of how to run Perl code directly from the command line.

```shell
# Unix/Linux
$perl  -e <perl code>
# Windows/DOS
C:>perl -e <perl code>
```

--------------------------------

### Find and suffix (added `.bak`)

Source: https://github.com/fechin/reference/blob/main/source/_posts/find.md

Find files starting with 'file*' and append '.bak' to their names.

```shell
$ find . -type f -name 'file*' -exec mv {} {}.bak\;
```

--------------------------------

### Option examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/grep.md

Forgets about case sensitivity

```shell
grep -i ^DA demo.txt
```

--------------------------------

### AJAX Request with Axios

Source: https://github.com/fechin/reference/blob/main/source/_posts/react.md

An example of making an AJAX GET request using the Axios library in a React component.

```javascript
import React from 'react';
import axios from 'axios';

export default function Weather(props) {
  function handleResponse(response) {
    console.log(response);
  }

  if (notifications) {
    return <p>notifications</p>;
  } else {
    let url = `https://notifications.com`;
    axios.get(url).then(handleResponse);
    return <p>Loading notifications..</p>;
  }
}
```

--------------------------------

### JSON output with full metadata

Source: https://github.com/fechin/reference/blob/main/source/_posts/claude-code.md

Example of getting Claude output with full metadata in JSON format.

```bash
$ claude -p "query" --output-format json
```

--------------------------------

### Setup Startup Script

Source: https://github.com/fechin/reference/blob/main/source/_posts/pm2.md

Generate and save a startup script to ensure PM2 processes restart on server boot/reboot.

```shell
$ pm2 save
```

--------------------------------

### Python Installation

Source: https://github.com/fechin/reference/blob/main/source/_posts/socket-io.md

Installs the Socket.IO client and server libraries for Python, with options for eventlet or aiohttp.

```bash
pip install python-socketio eventlet
# or
pip install python-socketio aiohttp
```

--------------------------------

### Slicing Python Lists

Source: https://github.com/fechin/reference/blob/main/source/_posts/python.md

Provides examples of basic list slicing using start and end indices, including negative indices.

```python
>>> a = ['spam', 'egg', 'bacon', 'tomato', 'ham', 'lobster']
>>> a[2:5]
['bacon', 'tomato', 'ham']
>>> a[-5:-2]
['egg', 'bacon', 'tomato']
>>> a[1:4]
['egg', 'bacon', 'tomato']
```

--------------------------------

### Variables - Variable Commands

Source: https://github.com/fechin/reference/blob/main/source/_posts/powershell.md

Examples of using commands to create, get, and remove variables, including options like ReadOnly and Constant.

```powershell
New-Variable -Name FirstName -Value Trevor
New-Variable FirstName -Value Trevor -Option <ReadOnly|Constant>

Get-Variable
Get-Variable | ? { $PSItem.Options -contains 'constant' }
Get-Variable | ? { $PSItem.Options -contains 'readonly' }

Remove-Variable -Name firstname
# Removes ReadOnly var
Remove-Variable -Name firstname -Force
```

--------------------------------

### Chat Client-Server Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/nc.md

Sets up a simple chat application where a server listens on a port and a client connects to it.

```shell
$ nc -lv 8000
```

```shell
$ nc 192.168.1.9 8000
```

--------------------------------

### Skill Commands

Source: https://github.com/fechin/reference/blob/main/source/_posts/openclaw.md

Commands for managing skills, including listing, checking readiness, getting info, searching, installing, and updating.

```bash
openclaw skills list
openclaw skills check      # readiness check
openclaw skills info <name>
openclaw skills search "browser"
openclaw skills install clawhub:browser
openclaw skills update
```

--------------------------------

### Database Connection Examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/symfony.md

Examples of DATABASE_URL configurations for different database systems (MySQL, MariaDB, PostgreSQL).

```bash
# MySQL 
DATABASE_URL="mysql://username:password@127.0.0.1:3306/db_name?serverVersion=X.Y.Z&charset=utf8mb4"

# MariaDB 
DATABASE_URL="mysql://username:password@127.0.0.1:3307/db_name?serverVersion=X.Y.Z-MariaDB&charset=utf8mb4"

# PostgreSQL 
DATABASE_URL="postgresql://username:password@127.0.0.1:5432/db_name?serverVersion=X.Y.Z&charset=utf8"
```

--------------------------------

### Hook Configuration Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/gemini-cli.md

Example of how to configure hooks in `settings.json` for different events like `BeforeTool` and `SessionStart`.

```json
{
  "hooks": {
    "BeforeTool": [
      {
        "type": "command",
        "command": "~/.gemini/hooks/validate-tool.sh",
        "matcher": "write_file",
        "timeout": 10000
      }
    ],
    "SessionStart": [
      {
        "type": "command",
        "command": "echo '{\"systemMessage\": \"Be concise.\"}'"
      }
    ]
  }
}
```

--------------------------------

### Custom Filter and Simple Tag

Source: https://github.com/fechin/reference/blob/main/source/_posts/django.md

Example of a custom Django filter for converting a string to lowercase and a simple tag to get the class name of an object.

```python
from django import template

register = template.Library()

@register.filter()
def lower(value):
    """Converts a string into all lowercase"""
    return value.lower()


@register.simple_tag
def to_class_name(object):
    return str(object.__class__.__name__)
```

--------------------------------

### Config Commands

Source: https://github.com/fechin/reference/blob/main/source/_posts/openclaw.md

Commands for managing OpenCLAW configuration, including showing file paths, getting/setting/unsetting values, validation, schema display, and guided setup.

```bash
# Show config file path
openclaw config file

# Get a value
openclaw config get gateway.port
openclaw config get channels.telegram.botToken

# Set a value
openclaw config set gateway.port 19001
openclaw config set \
  agents.defaults.model.primary \
  anthropic/claude-sonnet-4-6

# Unset a value
openclaw config unset gateway.port

# Validate config
openclaw config validate

# Print JSON schema
openclaw config schema

# Interactive guided setup
openclaw configure
```

--------------------------------

### Option examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/grep.md

Display 5 lines around matching string

```shell
grep -C 5 'Exception' error.log
```

--------------------------------

### Option examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/grep.md

Display 3 lines after matching string

```shell
grep -A 3 'Exception' error.log
```

--------------------------------

### JavaScript (Node.js) Installation

Source: https://github.com/fechin/reference/blob/main/source/_posts/socket-io.md

Installs the Socket.IO server and client libraries for Node.js.

```bash
npm install socket.io socket.io-client
```

--------------------------------

### Option examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/grep.md

Display 4 lines before matching string

```shell
grep -B 4 'Exception' error.log
```

--------------------------------

### XACK Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Example of using the XACK command. Note: The example shows an error, likely due to the command not being available in the specific Redis version or context used for the example.

```shell
redis> XACK mystream mygroup 1526569495631-0
ERR Unknown or disabled command 'XACK'
```

--------------------------------

### CSS Flexbox Simple example

Source: https://github.com/fechin/reference/blob/main/source/_posts/css3.md

A basic example of setting up a flex container.

```css
.container {
  display: flex;
}
```

```css
.container > div {
  flex: 1 1 auto;
}
```

--------------------------------

### Python Client and Server Setup

Source: https://github.com/fechin/reference/blob/main/source/_posts/socket-io.md

Sets up a Socket.IO client connection and a basic Python server using Flask and eventlet.

```python
import socketio
sio = socketio.Client()
sio.connect('http://localhost:3000')
```

```python
import socketio, eventlet, flask

app = flask.Flask(__name__)
sio = socketio.Server(cors_allowed_origins='*')
app = socketio.WSGIApp(sio, app)

@sio.event
def connect(sid, environ):
    print('Client connected:', sid)

if __name__ == '__main__':
    eventlet.wsgi.server(eventlet.listen(('', 3000)), app)
```

--------------------------------

### Install Command Line Tools

Source: https://github.com/fechin/reference/blob/main/source/_posts/homebrew.md

Installs the Command Line Tools (CLT) if not already installed, which is a prerequisite for Homebrew.

```bash
xcode-select --install
```

--------------------------------

### Namespaces - Client (All Languages)

Source: https://github.com/fechin/reference/blob/main/source/_posts/socket-io.md

Example of connecting to a specific namespace on the client.

```javascript
const adminSocket = io('/admin');
```

```python
sio.connect('http://localhost:3000/admin', namespaces=['/admin'])
```

--------------------------------

### Filter Examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/mitmproxy.md

Examples of mitmproxy filters.

```mitmproxy-filter
google\.com
```

```mitmproxy-filter
~q ~b test
```

```mitmproxy-filter
!(~q & ~t "text/html")
```

```mitmproxy-filter
":~q ~m GET:.*:/replacement.html"
```

--------------------------------

### Tagging Examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/latex.md

Examples of KaTeX tagging for equations.

```KaTeX
\tag{hi} x+y^{2x}
```

```KaTeX
\tag*{hi} x+y^{2x}
```

--------------------------------

### Initializing a New Project

Source: https://github.com/fechin/reference/blob/main/source/_posts/npm.md

Commands to initialize a new Node.js project, creating a package.json file.

```bash
npm init # Interactive setup
# or
npm init -y # Creates a package.json with default values
```

--------------------------------

### Install EJS

Source: https://github.com/fechin/reference/blob/main/source/_posts/ejs.md

Install EJS using npm.

```shell
$ npm install ejs
```

--------------------------------

### Option examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/grep.md

Return all lines which don't match the pattern

```shell
grep -v 'warning' /var/log/syslog
```

--------------------------------

### Start Redis Server

Source: https://github.com/fechin/reference/blob/main/source/_posts/redis.md

Starts the Redis server.

```shell
$ redis-server

```

--------------------------------

### Option examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/grep.md

Search only for the full word

```shell
grep -w "of" demo.txt
```

--------------------------------

### KaTeX Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/latex.md

An example of KaTeX syntax for a mathematical integral.

```KaTeX
% \f is defined as #1f(#2) using the macro
f\relax(x) = \int_{-\infty}^\infty
    f\hat\xi\,e^{2 \pi i \xi x}
    \,d\xi
```

--------------------------------

### Option examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/grep.md

Only show the matching part of the string

```shell
grep -o search_string filename
```

--------------------------------

### Basic Substitution Examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/sed.md

Common examples for substitution with sed.

```shell
$ sed 's/old/new/g' file.txt
$ sed 's/old/new/g' file.txt > new.txt

$ sed 's/old/new/g' -i file.txt
$ sed 's/old/new/g' -i.backup file.txt
```

--------------------------------

### C# (.NET) Client and Server Setup

Source: https://github.com/fechin/reference/blob/main/source/_posts/socket-io.md

Sets up a Socket.IO client connection and a basic C# server using Fleck.

```csharp
var socket = IO.Socket("http://localhost:3000");
socket.Connect();
```

```csharp
using Fleck;
var server = new WebSocketServer("ws://0.0.0.0:3000");
server.Start(socket =>
{
    socket.OnOpen = () => Console.WriteLine("Client connected");
});
```

--------------------------------

### Two Columns Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/quickref.md

Example of a two-column section layout.

```text
# Two Columns Example
╭┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈╮ ╭┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈╮
┆  1              ┆ ┆  2              ┆
╰┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈╯ ╰┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈╯
╭┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈╮
┆  3              ┆
╰┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈╯
```

--------------------------------

### One Column Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/quickref.md

Example of a one-column section layout.

```text
# One Column Example {.cols-1}
╭┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈╮
┆  1                                  ┆
╰┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈╯
╭┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈╮
┆  2                                  ┆
╰┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈╯
```

--------------------------------

### Unix and Linux Installation Commands

Source: https://github.com/fechin/reference/blob/main/source/_posts/perl.md

Commands to install Perl from source on Unix/Linux systems.

```shell
$tar -xzf perl-5.x.y.tar.gz
$cd perl-5.x.y
./Configure -de
$make
$make test
$make install
```

--------------------------------

### Examples

Source: https://github.com/fechin/reference/blob/main/source/_posts/jquery.md

Example of using jQuery selectors to manipulate elements.

```javascript
$('button').click(() => {
  $(':button').css('color', 'red');
});
```

--------------------------------

### Create a Repository

Source: https://github.com/fechin/reference/blob/main/source/_posts/git.md

Commands to initialize a new local repository or clone an existing one.

```shell
$ git init [project name]
```

```shell
$ git clone git_url
```

```shell
$ git clone git_url my_directory
```

--------------------------------

### Quick Setup: Open Dashboard

Source: https://github.com/fechin/reference/blob/main/source/_posts/openclaw.md

Command to open the OpenClaw dashboard and its default local URL.

```bash
openclaw dashboard
# Local default: http://127.0.0.1:18789/
```

--------------------------------

### Example

Source: https://github.com/fechin/reference/blob/main/source/_posts/jquery.md

Example of jQuery event handling and CSS manipulation.

```javascript
$('#menu').on('click', function () {
  $(this).hide();
});

$('body').css('background', 'red');
```