Python提供了很多代码库以方便开发人员使用。但是在多个项目同步开发中，不同项目所依赖的代码库的版本可能不一样。如果我们在同一个环境中维护着这些项目，将导致依赖库的版本错乱。为了解决这个问题，我们引入虚拟环境来做项目隔离。
本文介绍的脚本，提供了下列方法：
source env.sh init
python version number: Python3.10
Reading package lists… Done
Building dependency tree… Done
Reading state information… Done
Note, selecting ‘python3.10-venv’ for glob ‘Python3.10-venv’
The following NEW packages will be installed:
python3.10-venv
0 upgraded, 1 newly installed, 0 to remove and 6 not upgraded.
Need to get 0 B/5,716 B of archives.
After this operation, 28.7 kB of additional disk space will be used.
Selecting previously unselected package python3.10-venv.
(Reading database … 81266 files and directories currently installed.)
Preparing to unpack …/python3.10-venv_3.10.12-1~22.04.3_amd64.deb …
Unpacking python3.10-venv (3.10.12-1~22.04.3) …
Setting up python3.10-venv (3.10.12-1~22.04.3) …
Scanning processes…
Scanning candidates…
Scanning linux images…
Running kernel seems to be up-to-date.
Restarting services…
Service restarts being deferred:
/etc/needrestart/restart.d/dbus.service
systemctl restart networkd-dispatcher.service
systemctl restart systemd-logind.service
systemctl restart unattended-upgrades.service
systemctl restart user@1000.service
No containers need to be restarted.
No user sessions are running outdated binaries.
No VM guests are running outdated hypervisor (qemu) binaries on this host.
Create virtual environment
python version number: Python3.10
Reading package lists… Done
Building dependency tree… Done
Reading state information… Done
Note, selecting ‘python3.10-venv’ for glob ‘Python3.10-venv’
python3.10-venv is already the newest version (3.10.12-1~22.04.3).
0 upgraded, 0 newly installed, 0 to remove and 6 not upgraded.
The virtual environment already exists. If you need to create a new virtual environment, please execute the source env.sh del command to delete the virtual environment.
source env.sh del
Delete virtual environment
Currently in the virtual environment. Failed to delete the virtual environment. if you need to delete the virtual environment, please exit the virtual environment and then execute the source env.sh del command to delete the virtual environment. Or execute the source env.sh del force command to force delete the virtual environment.
source env.sh del force
Quit the virtual environment
Delete virtual environment
source env.sh enter
Enter the virtual environment
Currently in the virtual environment.
source env.sh quit
Currently not in the virtual environment.
Quit the virtual environment
source env.sh import
Currently not in the virtual environment.
The requirements.txt file does not exist. If you need to import the requirements.txt file, please execute the source env.sh export command to export the requirements.txt file from other virtual environment.
以requirements.txt中内容是numpy==1.26.3为例
Collecting numpy==1.26.3
Using cached numpy-1.26.3-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.whl (18.2 MB)
Installing collected packages: numpy
Successfully installed numpy-1.26.3
Import virtual environment
Currently not in the virtual environment.
Export virtual environment
The requirements.txt file already exists. If you need to update the requirements.txt file, remove requirements.txt and then execute the source env.sh export command to update the requirements.txt file.
source env.sh export force
Export virtual environment
source env.sh install numpy scipy
source env.sh install numpy scipy
Collecting numpy
Using cached numpy-1.26.3-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.whl (18.2 MB)
Collecting scipy
Using cached scipy-1.11.4-cp310-cp310-manylinux_2_17_x86_64.manylinux2014_x86_64.whl (36.4 MB)
Installing collected packages: numpy, scipy
Successfully installed numpy-1.26.3 scipy-1.11.4
Install libraries numpy scipy
source env.sh install numpy scipy
Currently not in the virtual environment.
Found existing installation: numpy 1.26.3
Uninstalling numpy-1.26.3:
Would remove:
/home/fangliang/numpy-example/.env/bin/f2py
/home/fangliang/numpy-example/.env/lib/python3.10/site-packages/numpy-1.26.3.dist-info/*
/home/fangliang/numpy-example/.env/lib/python3.10/site-packages/numpy.libs/libgfortran-040039e1.so.5.0.0
/home/fangliang/numpy-example/.env/lib/python3.10/site-packages/numpy.libs/libopenblas64_p-r0-0cf96a72.3.23.dev.so
/home/fangliang/numpy-example/.env/lib/python3.10/site-packages/numpy.libs/libquadmath-96973f99.so.0.0.0
/home/fangliang/numpy-example/.env/lib/python3.10/site-packages/numpy/*
Proceed (Y/n)? Y
Successfully uninstalled numpy-1.26.3
Found existing installation: scipy 1.11.4
Uninstalling scipy-1.11.4:
Would remove:
/home/fangliang/numpy-example/.env/lib/python3.10/site-packages/scipy-1.11.4.dist-info/*
/home/fangliang/numpy-example/.env/lib/python3.10/site-packages/scipy.libs/libgfortran-040039e1.so.5.0.0
/home/fangliang/numpy-example/.env/lib/python3.10/site-packages/scipy.libs/libopenblasp-r0-23e5df77.3.21.dev.so
/home/fangliang/numpy-example/.env/lib/python3.10/site-packages/scipy.libs/libquadmath-96973f99.so.0.0.0
/home/fangliang/numpy-example/.env/lib/python3.10/site-packages/scipy/*
Proceed (Y/n)? Y
Successfully uninstalled scipy-1.11.4
Uninstall libraries numpy scipy
source env.sh help
init: create virtual environment
enter: enter virtual environment
quit: quit virtual environment
del (force): delete virtual environment. If the force parameter is added, the virtual environment will be deleted forcibly
export (force): export virtual environment. If the force parameter is added, the requirements.txt file will be overwritten
import: import virtual environment
install: install libraries
uninstall : uninstall libraries
help: view help