无法在ubuntu 16.04上卸载python2包

Question

我正在尝试清除所有使用pip安装的python2.7包。你知道吗

所以我用这个命令：

sudo pip freeze | xargs pip uninstall -y

但我得到了一个错误：

Uninstalling pandocfilters-1.4.2:
Exception:
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/pip/_internal/basecommand.py", line 228, in main
    status = self.run(options, args)
  File "/usr/local/lib/python2.7/dist-packages/pip/_internal/commands/uninstall.py", line 68, in run
    auto_confirm=options.yes, verbose=self.verbosity > 0,
  File "/usr/local/lib/python2.7/dist-packages/pip/_internal/req/req_install.py", line 661, in uninstall
    uninstalled_pathset.remove(auto_confirm, verbose)
  File "/usr/local/lib/python2.7/dist-packages/pip/_internal/req/req_uninstall.py", line 219, in remove
    renames(path, new_path)
  File "/usr/local/lib/python2.7/dist-packages/pip/_internal/utils/misc.py", line 273, in renames
    shutil.move(old, new)
  File "/usr/lib/python2.7/shutil.py", line 303, in move
    os.unlink(src)
OSError: [Errno 13] Permission denied: '/usr/local/lib/python2.7/dist-packages/pandocfilters-1.4.2.dist-info/DESCRIPTION.rst'