+
−#!/usr/bin/env python
+
−# -*- coding: utf-8 -*-
+
−
+
−import re
+
−
+
−
+
−_find_unsafe = re.compile(r'[a-zA-Z0-9_^@%+=:,./-]').search
+
−
+
−
+
−def quote(s):
+
−    """Return a shell-escaped version of the string *s*."""
+
−    if not s:
+
−        return "''"
+
−
+
−    if _find_unsafe(s) is None:
+
−        return s
+
−
+
−    # use single quotes, and put single quotes into double quotes
+
−    # the string $'b is then quoted as '$'"'"'b'
+
−
+
−    return "'" + s.replace("'", "'\"'\"'") + "'"