情況說明

在ubuntu server 20.02下安裝了python 2.7， 3.8.5， 3.9。python默認(rèn)被設(shè)置在3.8.5下， 3.9是之前為了驗(yàn)證問題安裝的，現(xiàn)在并沒有在使用。

當(dāng)我安裝pyserial包的時(shí)候，發(fā)現(xiàn)這臺(tái)server并沒有安裝pip，于是安裝pip：

sudo apt-get install python3-pip

再安裝pyserial包

sudo pip3 install pyserial

此時(shí)在python下import serial會(huì)提示找不到包，檢查發(fā)現(xiàn)默認(rèn)運(yùn)行的是python 3.8.5，但是pyserial被安裝在python3.9下面。由于所有的腳本都是跑在3.8.5下，因此希望pyserial也安裝到3.8.5下，卸載沒有使用的python3.9：

sudo pip3 uninstall pyserial

sudo apt-get --purge remove python3-pip

sudo apt-get --purge remove python3.9

此時(shí)為python 3.8.5安裝pip3和pyserial，發(fā)現(xiàn)還是被裝在/user/lib/python3.9下面，在/usr執(zhí)行下面命令

find -name python3.9*

發(fā)現(xiàn)python3.9并沒有清除干凈

。/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

于是手動(dòng)刪除

1

find -name python3.9* | xargs sudo rm -rf

然后噩夢(mèng)開始，此時(shí)再安裝pip3，會(huì)提示已經(jīng)安裝

/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.

但執(zhí)行pip，又會(huì)說找不到

/usr$ sudo pip3 install pyserial

sudo： unable to execute /usr/bin/pip3： No such file or directory

如果再次卸載pip3， 提示錯(cuò)誤

Removing 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）

解決方法

sudo apt-get update

sudo apt-get upgrade

sudo apt --fix-broken install

dpkg --configure -a

apt-get download python3-minimal

sudo dpkg -i *python3*.deb

sudo apt-get -f install

sudo apt-get install python3-pip

sudo pip3 install pyserial

編輯：jq