Hello, there!

pmb/helpers/file.py

@@ -0,0 +1,27 @@
+"""
+Copyright 2017 Oliver Smith
+
+This file is part of pmbootstrap.
+
+pmbootstrap is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+pmbootstrap is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with pmbootstrap.  If not, see <http://www.gnu.org/licenses/>.
+"""
+def replace(path, old, new):
+    text = ""
+    with open(path, 'r') as handle:
+        text = handle.read()
+
+    text = text.replace(old, new)
+
+    with open(path, 'w') as handle:
+        handle.write(text)