Basic CLI with os.Args and flag

Context

Go provides two simple ways to read command‑line input:

• os.Args – a slice of strings containing program name and arguments.
• flag package – parses Unix‑style flags (-name value or --name value).

os.Args is good for positional arguments. flag is better for optional named flags.

Example

Use os.Args to print all arguments.

Code example

package main

import (
    "fmt"
    "os"
)

func main() {
    if len(os.Args) < 2 {
        fmt.Println("Usage: ./program <name>")
        return
    }
    name := os.Args[1]
    fmt.Printf("Hello, %s!\n", name)
}

Output

Hello, Alice!

Useful links

• os.Args documentation
• flag package documentation