Get the output of a shell command in node.js

Question

Get the output of a shell command in node.js

In a node.js, I'd like to find a way to obtain the output of a Unix terminal command. Is there any way to do this?

function getCommandOutput(commandString){
    //now how can I implement this function?
    //getCommandOutput("ls") should print the terminal output of the shell command "ls"
}

bash
node.js

Answer 1

Thats the way I do it in a project I am working now.

var exec = require('child_process').exec;
function execute(command, callback){
    exec(command, function(error, stdout, stderr){ callback(stdout); });
};

Example: Retrieving git user

module.exports.getGitUser = function(callback){
    execute("git config --global user.name", function(name){
        execute("git config --global user.email", function(email){
            callback({ name: name.replace("\n", ""), email: email.replace("\n", "") });
        });
    });
};

Answer 2

You're looking for child_process

var exec = require('child_process').exec;
var child;

child = exec(command,
   function (error, stdout, stderr) {
      console.log('stdout: ' + stdout);
      console.log('stderr: ' + stderr);
      if (error !== null) {
          console.log('exec error: ' + error);
      }
   });

As pointed out by Renato, there are some synchronous exec packages out there now too, see sync-exec that might be more what yo're looking for. Keep in mind though, node.js is designed to be a single threaded high performance network server, so if that's what you're looking to use it for, stay away from sync-exec kinda stuff unless you're only using it during startup or something.