Installing pythonstartup file

In your ~/.bashrc:

export PYTHONSTARTUP=$HOME/.pythonstartup

and put your python code in $HOME/.pythonstartup, like:

import rlcompleterimport readlinereadline.parse_and_bind("tab: complete")

Then run the interactive shell:

python

See the imports from PYTHONSTARTUP are processed. This only works in python interactive mode.

For more information about PYTHONSTARTUP variable, read the python man page:

$ man python

How to execute the python file defined in $PYTHONSTARTUP when you execute a file like python foobar.py

Run this command to find out where your OS has defined USER_SITE:

$ python -c "import site; site._script()" 

Mine says:

USER_SITE: '/home/el/.local/lib64/python2.7/site-packages'

Create a new file there called /home/el/.local/lib64/python2.7/site-packages/usercustomize.py, put this code in there:

try:    import your_things    import readline    print("ROCKETMAN!")except ImportError:    print("Can't load your things")    print("Either exit here, or perform remedial actions")    exit()

Close the terminal and reopen it to clear out any shenanigans.

Make a new file python foobar.py anywhere on the filesystem, put this code in there:

#Note there is no your_things module imported here.#Print your_things version:print(your_things.__version__)

Run it:

python foobar.py ROCKETMAN!'1.12.0'

What just happened.

You used the python sitewide specific python configuration hook and imported libraries in the usercustomize.py file which ran before foobar.py.

Documentation: https://docs.python.org/2/library/site.html

Where I found this trick: https://nedbatchelder.com/blog/201001/running_code_at_python_startup.html

On Windows you can put your startup script just about anywhere as long as you put its path into your PYTHONSTARTUP environment variable. On Windows the lettercase of environment variable names doesn't matter.

You can define the values of user and system environment variables as described in a somewhat related answer of mine here.