服务器：Amazon Linux
Uname -a:
Linux ip-10-0-6-228 4.14.77-70.59.amzn1.x86_64 #1 SMP Mon Nov 12
22:02:45 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
与python2.7兼容。我使用yum install -y python36安装了python3.6，并安装了以下软件包：
Installed:
python36.x86_64 0:3.6.5-1.9.amzn1
Dependency Installed:
python36-libs.x86_64 0:3.6.5-1.9.amzn1
python36-pip.noarch 0:9.0.3-1.26.amzn1
python36-setuptools.noarch 0:36.2.7-1.33.amzn1
我做了pip -V，并得到了pip 9.0.3 from /usr/lib/python2.7/dist-packages (python 2.7)。
我做了pip-3.6 -V并得到了：pip 9.0.3 from /usr/lib/python3.6/dist-packages (python 3.6)符合预期。
为pip3创建了符号链接。
[root@ip-10-0-6-228 bin]# ln -s /usr/bin/pip-3.6 /etc/alternatives/pip3
[root@ip-10-0-6-228 bin]# ln -s /etc/alternatives/pip3 /usr/bin/pip3
我再次pip3 -V做了，我得到了pip 9.0.3 from /usr/lib/python3.6/dist-packages (python 3.6)。到目前为止看起来还不错，我想将pip3从9.升级到18.。
我确实pip install --upgrade pip将pip2.7从9.升级到了18。
我想升级pip3，所以我做了pip3 install --upgrade pip3，然后得到了
[root@ip-10-0-6-228 bin]# pip3 install --upgrade pip3
Collecting pip3
Could not find a version that satisfies the requirement pip3 (from
versions: )
No matching distribution found for pip3
You are using pip version 9.0.3, however version 18.1 is available.
You should consider upgrading via the 'pip install --upgrade pip'
command.
我做了研究，终于尝试了pip3 install --upgrade pip
[root@ip-10-0-6-228 bin]# pip3 install --upgrade pip
Collecting pip
Using cached https://files.pythonhosted.org/packages/c2/d7/90f34cb0d83a6c5631cf71dfe64cc1054598c843a92b400e55675cc2ac37/pip-18.1-py2.py3-none-any.whl
Installing collected packages: pip
Found existing installation: pip 9.0.3
Uninstalling pip-9.0.3:
Successfully uninstalled pip-9.0.3
Successfully installed pip-18.1
[root@ip-10-0-6-228 bin]# pip3 -V
-bash: /usr/bin/pip3: No such file or directory
[root@ip-10-0-6-228 bin]# pip-3.6
Traceback (most recent call last):
File "/usr/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 658, in _build_master
ws.require(__requires__)
File "/usr/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 972, in require
needed = self.resolve(parse_requirements(requirements))
...
另外，点子也消失了。
[root@ip-10-0-6-228 bin]# pip -V
-bash: /usr/bin/pip: No such file or directory
[root@ip-10-0-6-228 bin]# pip
-bash: /usr/bin/pip: No such file or directory
再次，我从另一个来源发现pip3不是由pip管理的文件，因此重新安装了python36。
Installed:
python36.x86_64 0:3.6.5-1.9.amzn1
Complete!
然后我做了
[root@ip-10-0-6-228 ~]# pip3 -V
-bash: /usr/bin/pip3: No such file or directory
[root@ip-10-0-6-228 ~]# pip-3.6 -V
Traceback (most recent call last):
File "/usr/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 658, in _build_master
ws.require(__requires__)
File "/usr/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 972, in require
needed = self.resolve(parse_requirements(requirements))
File "/usr/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 863, in resolve
raise VersionConflict(dist, req).with_context(dependent_req)
pkg_resources.VersionConflict: (pip 18.1 (/usr/local/lib/python3.6/site-packages), Requirement.parse('pip==9.0.3'))
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/usr/bin/pip-3.6", line 6, in <module>
from pkg_resources import load_entry_point
File "/usr/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 3049, in <module>
@_call_aside
File "/usr/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 3033, in _call_aside
f(*args, **kwargs)
File "/usr/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 3062, in _initialize_master_working_set
working_set = WorkingSet._build_master()
File "/usr/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 660, in _build_master
return cls._build_from_requirements(__requires__)
File "/usr/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 673, in _build_from_requirements
dists = ws.resolve(reqs, Environment())
File "/usr/lib/python3.6/dist-packages/pkg_resources/__init__.py", line 858, in resolve
raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'pip==9.0.3' distribution was not found and is required by the application
然后我重新安装了python36-pip。
Installed:
python36-pip.noarch 0:9.0.3-1.26.amzn1
Complete!
然后我得到了：
[root@ip-10-0-6-228 ~]# pip-3.6 -V
pip 9.0.3 from /usr/lib/python3.6/dist-packages (python 3.6)
我看到它是9点。pip -V目前仍然无法正常工作。
[root@ip-10-0-6-228 ~]# pip -V
Traceback (most recent call last):
File "/usr/bin/pip", line 6, in <module>
from pkg_resources import load_entry_point
File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 3049, in <module>
@_call_aside
File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 3033, in _call_aside
f(*args, **kwargs)
File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 3062, in _initialize_master_working_set
working_set = WorkingSet._build_master()
File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 660, in _build_master
return cls._build_from_requirements(__requires__)
File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 673, in _build_from_requirements
dists = ws.resolve(reqs, Environment())
File "/usr/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 858, in resolve
raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'pip==9.0.3' distribution was not found and is required by the application
重新安装了python27和python27-pip（9.）。然后做了pip -V
[root@ip-10-0-6-228 ~]# pip -V
pip 9.0.3 from /usr/lib/python2.7/dist-packages (python 2.7)
然后一段时间后，与我的ec2的连接丢失并重新登录，然后执行pip3 -V和pip -V
Last login: Tue Jan 8 19:24:45 UTC 2019 on pts/0
[root@ip-10-0-6-228 ~]# pip -V
pip 18.1 from /usr/local/lib/python3.6/site-packages/pip (python 3.6)
[root@ip-10-0-6-228 ~]# pip3 -V
pip 18.1 from /usr/local/lib/python3.6/site-packages/pip (python 3.6)
令我惊讶的是，他们才18岁。在显示我9.之前，还是什么都没有。 有人可以解释一下如何解决吗？