Golang : Get command line arguments




Basically there are two ways to get arguments from the command line in Go.

The first way is via the flag package

flag.go

 package main

  import (
 "flag"
 "fmt"
  )

  func main() {
 flag.Parse() // get the arguments from command line

 arg := flag.Arg(0) // get the source directory from 1st argument

 fmt.Println("The first argument is " + arg)
 }

the output :

go run flag.go here

The first argument is here

go run flag.go there

The first argument is there

The second way is via the os package

osarg.go

 package main

 import (
 "os"
 "fmt"
 )

 func main () {


 if len(os.Args) != 3 {
 fmt.Printf("Usage : %s argument1 argument2 \n ", os.Args[0]) // return the program name back to %s
 os.Exit(1) // graceful exit
 }

 fmt.Println("First argument is : " + os.Args[1] + "\n")
 fmt.Println("Second argument is : " + os.Args[2] + "\n")
 }

Ok, this should cover the needs to get arguments from command line. Did I miss anything ? Leave your comment below.

  See also : Golang : Check if a directory exist or not





By Adam Ng

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