Golang : Execute shell command

A programming language will not be complete if there is no way for the developer to execute shell command. In this tutorial, we will show you how to execute a shell command in Go language.

We will use the dig command to retrieve the name servers of a website and output them.

Very often, dig command should be installed by default on most *nix based operating system. In case there is no dig command available, you can install it with the sudo yum install bind-utils or search for equivalent installation instruction for installing the BIND package. For Windows BIND package please download from http://www.isc.org

exec.go

 package main

 import (
  "fmt"
  "os/exec"
 )

 func main() {

  cmd := exec.Command("dig", "any", "google.com")
  out, err := cmd.Output()

  if err != nil {
 fmt.Println(err.Error())
 return
  }

  fmt.Print(string(out))
 }

Execute > go run exec.go will produce the following output

 ]# go run exec.go
 ;; Truncated, retrying in TCP mode.

 ; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.23.rc1.el6_5.1 <<>> any google.com
 ;; global options: +cmd
 ;; Got answer:
 ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 52756
 ;; flags: qr rd ra; QUERY: 1, ANSWER: 24, AUTHORITY: 0, ADDITIONAL: 0

 ;; QUESTION SECTION:
 ;google.com. IN ANY

 ;; ANSWER SECTION:
 google.com. 213 IN A 74.125.226.67
 google.com. 213 IN A 74.125.226.70
 google.com. 213 IN A 74.125.226.68
 google.com. 213 IN A 74.125.226.78
 google.com. 213 IN A 74.125.226.69
 google.com. 213 IN A 74.125.226.66
 google.com. 213 IN A 74.125.226.65
 google.com. 213 IN A 74.125.226.72
 google.com. 213 IN A 74.125.226.71
 google.com. 213 IN A 74.125.226.73
 google.com. 213 IN A 74.125.226.64
 google.com. 213 IN AAAA 2607:f8b0:4006:808::1007
 google.com. 513 IN MX 50 alt4.aspmx.l.google.com.
 google.com. 21513 IN SOA ns1.google.com. dns-admin.google.com. 2014021800 7200 1800 1209600 300
 google.com. 3513 IN TXT "v=spf1 include:_spf.google.com ip4:216.73.93.70/31 ip4:216.73.93.72/31 ~all"
 google.com. 513 IN MX 30 alt2.aspmx.l.google.com.
 google.com. 21513 IN NS ns4.google.com.
 google.com. 21513 IN NS ns2.google.com.
 google.com. 21513 IN NS ns3.google.com.
 google.com. 513 IN MX 10 aspmx.l.google.com.
 google.com. 21513 IN TYPE257 \# 19 0005697373756573796D616E7465632E636F6D
 google.com. 513 IN MX 20 alt1.aspmx.l.google.com.
 google.com. 513 IN MX 40 alt3.aspmx.l.google.com.
 google.com. 21513 IN NS ns1.google.com.

 ;; Query time: 21 msec
 ;; SERVER: 8.8.4.4#53(8.8.4.4)
 ;; WHEN: Tue May 13 04:43:46 2014
 ;; MSG SIZE  rcvd: 577

You can change the following code

 cmd := exec.Command("dig","any","google.com")

to

 application_name = "dig"
 arg_0 = "any"
 arg_1 = "google.com"

 cmd := exec.Command(application_name,arg_0,arg_1)

for readability purpose. Also, arguments must be separated in this manner instead of lumping everything into a string. Hope this tutorial will help you in learning more about Golang.

References:

OS Package