python -c 'import pip; [pip.main(["install", "--upgrade", d.project_name]) for d in pip.get_installed_distributions()]'

一行！

使用pipupgrade。。。最新版本2019

$ pip install pipupgrade
$ pipupgrade --verbose --latest --yes

pipupgrade帮助您从requirements.txt文件升级系统、本地或软件包！它还选择性地升级不破坏更改的包。

pipupgrade还确保升级多个Python环境中的包。它与Python2.7+、Python23.4+和pip9+、pip10+、pip18+、pip19+兼容。

注：我是该工具的作者。

通过拉取请求发送给pip人员；同时使用我写的这个pip库解决方案：

from pip import get_installed_distributions
from pip.commands import install

install_cmd = install.InstallCommand()

options, args = install_cmd.parse_args([package.project_name
                                        for package in
                                        get_installed_distributions()])

options.upgrade = True
install_cmd.run(options, args)  # Chuck this in a try/except and print as wanted

以下是通过pip更新所有Python 3包（在激活的virtualenv中）的代码：

import pkg_resources
from subprocess import call

for dist in pkg_resources.working_set:
    call("python3 -m pip install --upgrade " + dist.project_name, shell=True)

下面是用Python编写脚本的另一种方法：

import pip, tempfile, contextlib

with tempfile.TemporaryFile('w+') as temp:
    with contextlib.redirect_stdout(temp):
        pip.main(['list', '-o'])
    temp.seek(0)
    for line in temp:
        pk = line.split()[0]
        print('--> updating', pk, '<--')
        pip.main(['install', '-U', pk])

pip_upgrade_outdated（基于此旧脚本）完成此任务。根据其文件：

usage: pip_upgrade_outdated [-h] [-3 | -2 | --pip_cmd PIP_CMD]
                            [--serial | --parallel] [--dry_run] [--verbose]
                            [--version]

Upgrade outdated python packages with pip.

optional arguments:
  -h, --help         show this help message and exit
  -3                 use pip3
  -2                 use pip2
  --pip_cmd PIP_CMD  use PIP_CMD (default pip)
  --serial, -s       upgrade in serial (default)
  --parallel, -p     upgrade in parallel
  --dry_run, -n      get list, but don't upgrade
  --verbose, -v      may be specified multiple times
  --version          show program's version number and exit

步骤1：

pip install pip-upgrade-outdated

第2步：

pip_upgrade_outdated