Shell

Set up a shell command as a string and run it. You could run a shell command like date or even access programming language CLI tool like python or node.

This is using the exec builtin module. Similar to using the subprocess module in Python.

See exec package in Go’s standard packages.

Syntax

Import

import (
  "os/exec"
)

Command

You could pass something simple like "ls" or with arguments like "ls -l".

cmd := exec.Command("COMMAND")

The result will be of type exec.Cmd.

You will get an error on invalid command if you have spaces in your command. So use spaces:

exec.Command("ls")
exec.Command("ls", "-l")
exec.Command("bash", "greet.sh")

Run

If you don’t care about the output.

exec.Command("COMMAND").Run()

Or

cmd := exec.Command("COMMAND").
cmd.Run()

Output

output, err := exec.Command("COMMAND").Output()

Use .Output() to get stdout.

Use .CombinedOutput() to get stdout and stderr.

Examples

Run without checking output

cmd := exec.Command("firefox")

err := cmd.Run()

if err != nil {
    log.Fatal(err)
}

Run scripts

// Or "/bin/sh" for portability.
shell := "bash" 
path := "./my_script.sh"

exec.Command(shell, path)

Execute binary or executable script

exec.Command("date")

exec.Command("./my_executable.sh")

A fuller example:

• main.go

    package main
  
    import (
        "fmt"
        "log"
        "os/exec"
    )
  
    func main() {
        cmd := "date"
        out, err := exec.Command(cmd).Output()
        if err != nil {
            log.Fatal(err)
        }
  
        fmt.Printf("The date is: %s\n", out)
    }
  

Result:

$ go run main.go

The date is: Thu 25 Feb 2021 17:42:46 SAST

Handle errors and output

output, err := exec.Command("COMMAND".Output()

if err != nil {
    log.Fatal(err)
}

fmt.Printf("Output is %s\n", output)