Executing a Bash Script from Golang

I am trying to figure out a way to execute a script (.sh) file from Golang. I have found a couple of easy ways to execute commands (e.g. os/exec), but what I am looking to do is to execute an entire sh file (the file sets variables etc.).

Using the standard os/exec method for this does not seem to be straightforward: both trying to input "./script.sh" and loading the content of the script into a string do not work as arguments for the exec function.

for example, this is an sh file that I want to execute from Go:

OIFS=$IFS;
IFS=",";

# fill in your details here
dbname=testDB
host=localhost:27017
collection=testCollection
exportTo=../csv/

# get comma separated list of keys. do this by peeking into the first document in the collection and get his set of keys
keys=`mongo "$host/$dbname" --eval "rs.slaveOk();var keys = []; for(var key in db.$collection.find().sort({_id: -1}).limit(1)[0]) { keys.push(key); }; keys;" --quiet`;
# now use mongoexport with the set of keys to export the collection to csv
mongoexport --host $host -d $dbname -c $collection --fields "$keys" --csv --out $exportTo$dbname.$collection.csv;

IFS=$OIFS;

from the Go program:

out, err := exec.Command(mongoToCsvSH).Output()
	if err != nil {
		log.Fatal(err)
	}
	fmt.Printf("output is %s\n", out)

where mongoToCsvSH can be either the path to the sh or the actual content - both do not work.

Any ideas how to achieve this?

For your shell script to be directly runnable you have to:

1. Start it with #!/bin/sh (or #!/bin/bash, etc).

2. You have to make it executable, aka chmod +x script.

If you don't want to do that, then you will have to execute /bin/sh with the path to the script.

cmd := exec.Command("/bin/sh", mongoToCsvSH)

This worked for me

func Native() string {
    cmd, err := exec.Command("/bin/sh", "/path/to/file.sh").Output()
	if err != nil {
	fmt.Printf("error %s", err)
	}
	output := string(cmd)
	return output
}

You need to execute /bin/sh and pass the script itself as an argument.

This allows you to pass the arguments as well as get the output of the script in the Stdout or Stderr.

import (
	"github.com/sirupsen/logrus"
	"os"
	"os/exec"
)

func Execute(script string, command []string) (bool, error) {

	cmd := &exec.Cmd{
		Path:   script,
		Args:   command,
		Stdout: os.Stdout,
		Stderr: os.Stderr,
	}

	c.logger.Info("Executing command ", cmd)

	err := cmd.Start()
	if err != nil {
		return false, err
	}

	err = cmd.Wait()
	if err != nil {
		return false, err
	}

	return true, nil
}

Calling example:

command := []string{
	"/<path>/yourscript.sh",
	"arg1=val1",
	"arg2=val2",
}

Execute("/<path>/yourscript.sh", command)