情况说明
在ubuntu server 20.02下安装了python 2.7, 3.8.5, 3.9。python默认被设置在3.8.5下， 3.9是之前为了验证问题安装的，现在并没有在使用。
当我安装pyserial包的时候，发现这台server并没有安装pip，于是安装pip:1
sudo apt-get install python3-pip
再安装pyserial包1
sudo pip3 install pyserial
此时在python下import serial会提示找不到包，检查发现默认运行的是python 3.8.5，但是pyserial被安装在python3.9下面。由于所有的脚本都是跑在3.8.5下，因此希望pyserial也安装到3.8.5下，卸载没有使用的python3.9:1
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3sudo pip3 uninstall pyserial
sudo apt-get --purge remove python3-pip
sudo apt-get --purge remove python3.9
此时为python 3.8.5安装pip3和pyserial，发现还是被装在/user/lib/python3.9下面，在/usr执行下面命令1
find -name python3.9*
发现python3.9并没有清除干净1
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25./bin/python3.9
./lib/python3.9
./share/man/man1/python3.9.1.gz
./share/binfmts/python3.9
./share/doc/python3.9-doc
./share/doc/python3.9
./share/doc/python3.9/html/python3.9.devhelp.gz
./share/doc/python3.9-minimal
./share/doc-base/python3.9-lib
./share/doc-base/python3.9-inst
./share/doc-base/python3.9-api
./share/doc-base/python3.9-tut
./share/doc-base/python3.9-new
./share/doc-base/python3.9-ext
./share/doc-base/python3.9-dist
./share/doc-base/python3.9-ref
./share/lintian/overrides/python3.9-doc
./share/lintian/overrides/python3.9-minimal
./share/devhelp/books/python3.9
./share/info/python3.9.info.gz
./share/info/python3.9
./include/python3.9
./include/x86_64-linux-gnu/python3.9
./include/x86_64-linux-gnu/python3.9d
./include/python3.9d
于是手动删除1
find -name python3.9* | xargs sudo rm -rf
然后噩梦开始，此时再安装pip3，会提示已经安装1
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6/usr$ sudo apt-get install python3-pip
Reading package lists... Done
Building dependency tree
Reading state information... Done
python3-pip is already the newest version (20.0.2-5ubuntu1.5).
0 upgraded, 0 newly installed, 0 to remove and 57 not upgraded.
但执行pip，又会说找不到1
2/usr$ sudo pip3 install pyserial
sudo: unable to execute /usr/bin/pip3: No such file or directory
如果再次卸载pip3, 提示错误1
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12Removing python3-pip (20.0.2-5ubuntu1.5) ...
/var/lib/dpkg/info/python3-pip.prerm: 6: py3clean: not found
dpkg: error processing package python3-pip (--remove):
installed python3-pip package pre-removal script subprocess returned error exit status 127
dpkg: too many errors, stopping
/var/lib/dpkg/info/python3-pip.postinst: 6: py3compile: not found
dpkg: error while cleaning up:
installed python3-pip package post-installation script subprocess returned error exit status 127
Errors were encountered while processing:
python3-pip
Processing was halted because there were too many errors.
E: Sub-process /usr/bin/dpkg returned an error code (1)
解决方法
1 | sudo apt-get update |