You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: exec.go
    path of file: ./repos/juju/state/backups
    
    the code of the file until where you have to start completion: // Copyright 2014 Canonical Ltd.
// Licensed under the AGPLv3, see LICENCE file for details.

package backups

import (
	"os/exec"
	"strings"

	"github.com/juju/errors"
)

// runCommand execs the provided command. It exists
// here so it can be overridden in export_test.go
func runCommand(cmd string, args ...string) error {
	logger.Tracef("runCommand cmd=%s, args=%s", cmd, args)
	command := exec.Command(cmd, args...)
	out, err := command.Combin
    
func runCommand(cmd string, args ...string) error {
	logger.Tracef("runCommand cmd=%s, args=%s", cmd, args)
	command := exec.Command(cmd, args...)
	out, err := command.CombinedOutput()
	if err == nil {
		logger.Tracef("runCommand succeeded, output is:\n%s", out)
		return nil
	}
	logger.Tracef("runCommand error %v; output is:\n%s", out)
	if _, ok := err.(*exec.ExitError); ok && len(out) > 0 {
		return errors.Errorf(
			"error executing %q: %s",
			cmd,
			strings.Replace(string(out), "\n", "; ", -1),
		)
	}
	return errors.Annotatef(err, "error executing %q", cmd)
}