How to save a Python interactive session?

IPython is extremely useful if you like using interactive sessions. For example for your use-case there is the %save magic command, you just input %save my_useful_session 10-20 23 to save input lines 10 to 20 and 23 to my_useful_session.py (to help with this, every line is prefixed by its number).

Furthermore, the documentation states:

This function uses the same syntax as %history for input ranges, then saves the lines to the filename you specify.

This allows for example, to reference older sessions, such as

%save current_session ~0/
%save previous_session ~1/

Look at the videos on the presentation page to get a quick overview of the features.

From Andrew Jones's website (archived):

import readline
readline.write_history_file('/home/ahj/history')

There is a way to do it. Store the file in ~/.pystartup...

# Add auto-completion and a stored history file of commands to your Python
# interactive interpreter. Requires Python 2.0+, readline. Autocomplete is
# bound to the Esc key by default (you can change it - see readline docs).
#
# Store the file in ~/.pystartup, and set an environment variable to point
# to it:  "export PYTHONSTARTUP=/home/user/.pystartup" in bash.
#
# Note that PYTHONSTARTUP does *not* expand "~", so you have to put in the
# full path to your home directory.

import atexit
import os
import readline
import rlcompleter

historyPath = os.path.expanduser("~/.pyhistory")

def save_history(historyPath=historyPath):
    import readline
    readline.write_history_file(historyPath)

if os.path.exists(historyPath):
    readline.read_history_file(historyPath)

atexit.register(save_history)
del os, atexit, readline, rlcompleter, save_history, historyPath

and then set the environment variable PYTHONSTARTUP in your shell (e.g. in ~/.bashrc):

export PYTHONSTARTUP=$HOME/.pystartup

You can also add this to get autocomplete for free:

readline.parse_and_bind('tab: complete')

Please note that this will only work on *nix systems. As readline is only available in Unix platform.

Also, reinteract gives you a notebook-like interface to a Python session.

In addition to IPython, a similar utility bpython has a "save the code you've entered to a file" feature

In IPython, I first use

In [2]: %hist

to view my past code. I select the chunk I want to save and then paste it into file my_file.py using the %%file magic (short for %%writefile)

In [3]: %%file my_file.py
   ...: # paste code here 
   ...:  
   ...:  

hitting return two times in the end.

To append to file use the option -a: %%file -a my_file.py.

If needed, I can list, edit, etc. the file in the underlying command line using the exclamation mark

In [5]: !ls -l my_file.py
In [6]: !vi my_file.py

To save input and output on XUbuntu:

1. In XWindows, run iPython from the Xfce terminal app
2. click Terminal in the top menu bar and look for save contents in the dropdown

I find this saves the input and output, going all the way back to when I opened the terminal. This is not ipython specific, and would work with ssh sessions or other tasks run from the terminal window.

You can use built-in function open: I use it in all of my programs in which I need to store some history (Including Calculator, etc.) for example:

#gk-test.py or anything else would do
try: # use the try loop only if you haven't created the history file outside program
    username = open("history.txt").readline().strip("\n")
    user_age = open("history.txt").readlines()[1].strip("\n")
except FileNotFoundError:
    username = input("Enter Username: ")
    user_age = input("Enter User's Age: ")
    open("history.txt", "w").write(f"{username}\n{user_age}")
#Rest of the code is secret! try it your own!

I would thank to all of them who liked my comments! Thank you for reading this!