diff --git a/game.gd b/game.gd
index 8735b48..d4e8eeb 100644
--- a/game.gd
+++ b/game.gd
@@ -1,12 +1,19 @@
 extends Node
 
+var tmp_prefix = "/tmp/"
 var cwd
+var global_shell
 
 func _ready():
-	cwd = exec("pwd", [], true)
+	global_shell = Shell.new()
+	global_shell.cd(tmp_prefix)
+	
+	cwd = global_shell.run("pwd")
+	# Remove trailing newline.
+	cwd = cwd.substr(0,len(cwd)-1)
 
 # Run a simple command with arguments, blocking, using OS.execute.
-func exec(command, args=[], remote_trailing_newline=false):
+func exec(command, args=[]):
 	var debug = true
 	if debug:
 		print("game.exec: %s [%s]" % [command, PoolStringArray(args).join(", ")])
@@ -17,9 +24,6 @@ func exec(command, args=[], remote_trailing_newline=false):
 	
 	if debug:
 		print(output)
-	
-	if remote_trailing_newline:
-		output = output.substr(0,len(output)-1)
 
 	return output
 
diff --git a/main.gd b/main.gd
index 661571e..65466ef 100644
--- a/main.gd
+++ b/main.gd
@@ -46,18 +46,17 @@ func load_level(id):
 	var levels = list_levels()
 	
 	var level = levels[id]
-	var tmp_prefix = "/tmp/"
 	var level_prefix = "res://levels/"
 	
-	var goal_repository_path = tmp_prefix+"goal/"
-	var active_repository_path = tmp_prefix+"active/"
+	var goal_repository_path = game.tmp_prefix+"goal/"
+	var active_repository_path = game.tmp_prefix+"active/"
 	var goal_script = level_prefix+level+"/goal"
 	var active_script = level_prefix+level+"/start"
 	
 	var description = game.read_file(level_prefix+level+"/description")
 	$LevelDescription.bbcode_text = description
 	
-	# Danger zone! We're actually destroying stuff here.
+	# We're actually destroying stuff here.
 	# Make sure that active_repository is in a temporary directory.
 	var expected_prefix = "/tmp"
 	if active_repository_path.substr(0,4) != expected_prefix:
@@ -67,6 +66,7 @@ func load_level(id):
 		push_error("Refusing to delete a directory that does not start with %s" % expected_prefix)
 		get_tree().quit()
 	
+	# Danger zone!
 	game.exec("rm", ["-rf", active_repository_path])
 	game.exec("rm", ["-rf", goal_repository_path])
 	
@@ -80,8 +80,7 @@ func construct_repo(script, path):
 	# Becase in an exported game, all assets are in a .pck file, we need to put
 	# the script somewhere in the filesystem.
 	var content = game.read_file(script)
-	var tmp_prefix = "/tmp"
-	var script_path = tmp_prefix+"/git-hydra-script"
+	var script_path = game.tmp_prefix+"/git-hydra-script"
 	game.write_file(script_path, content)
 	
 	var shell = Shell.new()
diff --git a/shell.gd b/shell.gd
index 2bba1bf..701f16e 100644
--- a/shell.gd
+++ b/shell.gd
@@ -2,9 +2,14 @@ extends Node
 class_name Shell
 
 var _cwd
+var _fake_editor
 
 func _init():
-	pass
+	# Copy fake-editor to tmp directory (because the original might be in a .pck file).
+	_fake_editor = game.tmp_prefix + "fake-editor"
+	var content = game.read_file("res://scripts/fake-editor")
+	game.write_file(_fake_editor, content)
+	run("chmod u+x " + _fake_editor)
 	
 func cd(dir):
 	_cwd = dir
@@ -18,8 +23,7 @@ func run(command):
 		print("$ %s" % command)
 	
 	var env = {}
-	env["EDITOR"] = game.cwd+"/scripts/fake-editor"
-	env["TEST"] = "hi"
+	env["EDITOR"] = _fake_editor
 	
 	var hacky_command = ""
 	for variable in env: