Assuming pyserial
is not already installed, running these two commands will yield approximately the following output:
$ pip install pyserial
Collecting pyserial
Using cached pyserial-3.5-py2.py3-none-any.whl (90 kB)
Installing collected packages: pyserial
Successfully installed pyserial-3.5
$ pip install pySerial
Requirement already satisfied: pySerial in <redacted>/pyserial/lib/python3.8/site-packages (3.5)
I.e. the first command installs the package, while the second command just says that it’s already installed and does nothing. Trying to install PYSERIAL, pySERIAL, PysERiAl, etc. will all yield the same result.
Are you seeing something different?