Add util.uncomment() function

copied from fabric v1

rattail_fabric2/util.py

@@ -268,3 +268,38 @@ def sed(c, filename, before, after, limit='', use_sudo=False, backup='.bak',
     return func(command,
                 # shell=shell
     )
+
+
+def uncomment(c, filename, regex, use_sudo=False, char='#', backup='.bak',
+    # shell=False,
+):
+    """
+    NOTE: This was copied from the upstream ``fabric.contrib.files`` (v1) module.
+
+    Attempt to uncomment all lines in ``filename`` matching ``regex``.
+
+    The default comment delimiter is `#` and may be overridden by the ``char``
+    argument.
+
+    This function uses the `sed` function, and will accept the same
+    ``use_sudo``, ``shell`` and ``backup`` keyword arguments that `sed` does.
+
+    `uncomment` will remove a single whitespace character following the comment
+    character, if it exists, but will preserve all preceding whitespace.  For
+    example, ``# foo`` would become ``foo`` (the single space is stripped) but
+    ``    # foo`` would become ``    foo`` (the single space is still stripped,
+    but the preceding 4 spaces are not.)
+
+    .. versionchanged:: 1.6
+        Added the ``shell`` keyword argument.
+    """
+    return sed(
+        c,
+        filename,
+        before=r'^([[:space:]]*)%s[[:space:]]?' % char,
+        after=r'\1',
+        limit=regex,
+        use_sudo=use_sudo,
+        backup=backup,
+        # shell=shell
+    )