Go by Example: Command-Line Arguments

Command-line arguments are a common way to parameterize execution of programs. For example, go run hello.go uses run and hello.go arguments to the go program.

 
package main
 
import (
    "fmt"
    "os"
)
 
func main() {

os.Args provides access to raw command-line arguments. Note that the first value in this slice is the path to the program, and os.Args[1:] holds the arguments to the program.

 
    argsWithProg := os.Args
    argsWithoutProg := os.Args[1:]

You can get individual args with normal indexing.

 
    arg := os.Args[3]
 
    fmt.Println(argsWithProg)
    fmt.Println(argsWithoutProg)
    fmt.Println(arg)
}

To experiment with command-line arguments it’s best to build a binary with go build first.

 
$ go build command-line-arguments.go
$ ./command-line-arguments a b c d
[./command-line-arguments a b c d]       
[a b c d]
c

Next we’ll look at more advanced command-line processing with flags.

Next example: Command-Line Flags.

by Mark McGranaghan and Eli Bendersky | source | license