Checking out the flag package, Go’s built in command line argument parser. Here’s a simple example:

// flag.go
package main

import (
  "flag"
  "fmt"
)

var code *int = flag.Int("areacode", 716, "give me your codes")

func main() {
  fmt.Printf("Testing out flags!\n");
  flag.Parse();
  fmt.Println("areacode has value ", *code);
}

# Makefile
include $(GOROOT)/src/Make.$(GOARCH)
 
TARG=flag
GOFILES=\
        flag.go
 
include $(GOROOT)/src/Make.cmd

Compile and run away:

% make
/Users/qrush/Progs/8g -o _go_.8 flag.go
/Users/qrush/Progs/8l -o flag _go_.8

% ./flag
Testing out flags!
areacode has value  716

% ./flag -areacode=585
Testing out flags!
areacode has value  585

Mindblowing, I know. Also cool: flag.PrintDefaults() gives a nice printout of the command line arguments with default values.