Variable Declaration
# Declaring variables
name = "John"
age = 30
is_active = True
Lists
# Creating a list
numbers = [1, 2, 3, 4, 5]

# Appending to a list
numbers.append(6)

# Accessing list elements
first_number = numbers[0]  # 1
Dictionaries
# Creating a dictionary
person = {"name": "John", "age": 30}

# Accessing dictionary values
name = person["name"]

# Adding new key-value pairs
person["city"] = "New York"
Loops
# For loop
for i in range(5):
    print(i)

# While loop
count = 0
while count < 5:
    print(count)
    count += 1
Conditionals
# If, elif, else
if age < 20:
    print("Teenager")
elif age < 60:
    print("Adult")
else:
    print("Senior")
Functions
# Defining a function
def greet(name):
    return "Hello " + name

# Calling a function
greeting = greet("John")
print(greeting)
File Handling
# Writing to a file
with open('example.txt', 'w') as file:
    file.write('Hello, World!')

# Reading from a file
with open('example.txt', 'r') as file:
    content = file.read()
    print(content)
Exception Handling
# Try, except block
try:
    result = 10 / 0
except ZeroDivisionError:
    print("Divided by zero!")
Modules
# Importing a module
import math

# Using a function from the math module
result = math.sqrt(16)  # 4.0
Variable
NAME="John"
echo $NAME
echo "$NAME"
echo "${NAME}
Condition
if [[ -z "$string" ]]; then
  echo "String is empty"
elif [[ -n "$string" ]]; then
  echo "String is not empty"
fi
Chain command

Chain if the first command succeds

apt update -y && apt upgrade -y

Chain if the first command fails

apt update -y || sudo apt update -y
Pipe
ls -l | grep "config"
Disk Space
df -h
Search
find . -name "*.txt"
Output
ls > files.txt
Strings
str := "Hello"

Multiline string

str := `Multiline
string`
Numbers

Typical types

num := 3          // int
num := 3.         // float64
num := 3 + 4i     // complex128
num := byte('a')  // byte (alias for uint8)

Other Types

var u uint = 7        // uint (unsigned)
var p float32 = 22.7  // 32-bit float
Arrays
// var numbers [5]int
numbers := [...]int{0, 0, 0, 0, 0}
Pointers
func main () {
  b := *getPointer()
  fmt.Println("Value is", b)

func getPointer () (myPointer *int) {
  a := 234
  return &a

a := new(int)
*a = 234

Pointers point to a memory location of a variable. Go is fully garbage-collected.

Type Conversion
i := 2
f := float64(i)
u := uint(i)
Slice
slice := []int{2, 3, 4}

slice := []byte("Hello")
Condition
if day == "sunday" || day == "saturday" {
  rest()
} else if day == "monday" && isTired() {
  groan()
} else {
  work()
}

if _, err := doThing(); err != nil {
  fmt.Println("Uh oh")
Switch
switch day {
  case "sunday":
    // cases don't "fall through" by default!
    fallthrough

  case "saturday":
    rest()

  default:
    work()
}
Loop
for count := 0; count <= 10; count++ {
  fmt.Println("My counter is at", count)
}

entry := []string{"Jack","John","Jones"}
for i, val := range entry {
  fmt.Printf("At position %d, the character %s is present\n", i, val)

n := 0
x := 42
for n != x {
  n := guess()
}
Hello World

A sample go program is show here.

package main

import "fmt"

func main() {
  message := greetMe("world")
  fmt.Println(message)
}

func greetMe(name string) string {
  return "Hello, " + name + "!"
}

Run the program as below:

$ go run hello.go
Variables

Normal Declaration:

var msg string
msg = "Hello"

Shortcut:

msg := "Hello"
Constants
const Phi = 1.618
Condition
if day == "sunday" || day == "saturday" {
  rest()
} else if day == "monday" && isTired() {
  groan()
} else {
  work()
}

if _, err := doThing(); err != nil {
  fmt.Println("Uh oh")