Use spawn instead of exec.

git.js

@@ -1,7 +1,5 @@
 // imports
-var fs = require('fs');
-var path = require('path');
-var exec = require('child_process').exec;
+var spawn = require('child_process').spawn;
 
 // Class Git
 var Git = module.exports = function (options) {
@@ -12,7 +10,7 @@ var Git = module.exports = function (options) {
   this.cwd = options.cwd || process.cwd();
   delete options.cwd;
 
-  this.args = Git.optionsToString(options);
+  this.args = Git.optionsToArray(options);
 };
 
 // git.exec(command [[, options], args ], callback)
@@ -24,24 +22,56 @@ Git.prototype.exec = function (command, options, args, callback) {
     args = [];
   } else if (arguments.length == 3) {
     args = arguments[1];
-    options = [];
+    options = {};
   }
 
-  args = args.join(' ');
-  options = Git.optionsToString(options)
+  // Put all the args and options together and send as one array to spawn.
+  var cmdArgs = this.args
+      .concat(command)
+      .concat(Git.optionsToArray(options))
+      .concat(args);
+
+  this.spawnCommand(this.binary, cmdArgs, callback);
+};
+
+/**
+ * Spawns command
+ *
+ * @param {string} binary
+ * @param {Array} cmdArgs
+ * @param {function} callback
+ */
+Git.prototype.spawnCommand = function(binary, cmdArgs, callback) {
+  var gitproc = spawn(binary, cmdArgs, { cwd: this.cwd }),
+      output = '',
+      errorOutput = '';
+
+  // collect stdout
+  gitproc.stdout.on('data', function(data) {
+    output += data;
+  });
+
+  // collect stderr
+  gitproc.stderr.on('data', function(data) {
+    errorOutput += data;
+  });
 
-  var cmd = this.binary + ' ' + this.args + ' ' + command + ' ' + options + ' '
-    + args;
+  gitproc.on('close', function(code) {
+    if (code === 0) {
+      callback(null, output);
+    }
+    else {
+      callback(new Error(errorOutput), output);
+    }
+  });
 
-  exec(cmd, {
-    cwd: this.cwd
-  }, function (err, stdout, stderr) {
-    callback(err, stdout);
+  gitproc.on('error', function(err) {
+    callback(err);
   });
 };
 
-// converts an object that contains key value pairs to a argv string
-Git.optionsToString = function (options) {
+// converts an object that contains key value pairs to a args array suitable for child_process.spawn
+Git.optionsToArray = function (options) {
   var args = [];
 
   for (var k in options) {
@@ -61,6 +91,5 @@ Git.optionsToString = function (options) {
         args.push('--'+k+'='+val);
     }
   }
-
-  return args.join(' ');
+  return args;
 };