Is there a way to tell the interactive Python shell to preserve its history of executed commands between sessions?
While a session is running, after commands have been executed, I can arrow up and access said commands, I'm just wondering if there is some way for a certain number of these commands to be saved until the next time I use the Python shell.
This would be very useful since I find myself reusing commands in a session, that I used at the end of the last session.
Sure you can, with a small startup script. From Interactive Input Editing and History Substitution in the python tutorial:
# 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=~/.pystartup" in bash.
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
From Python 3.4 onwards, the interactive interpreter supports autocompletion and history out of the box:
Tab-completion is now enabled by default in the interactive interpreter on systems that support
readline. History is also enabled by default, and is written to (and read from) the file~/.python-history.
.pyhistory file to the virtual environment folder instead of user home folder.Use IPython.
You should, anyway, because it's awesome: persistent command history is just one of the many many ways it's better than the stock Python shell.
This is also required for Python 3 when using a virtual environment.
I use a slightly different version which keeps a history file per virtual environment:
import sys
if sys.version_info >= (3, 0) and hasattr(sys, 'real_prefix'): # in a VirtualEnv
import atexit, os, readline, sys
PYTHON_HISTORY_FILE = os.path.join(os.environ['VIRTUAL_ENV'], '.python_history')
if os.path.exists(PYTHON_HISTORY_FILE):
readline.read_history_file(PYTHON_HISTORY_FILE)
atexit.register(readline.write_history_file, PYTHON_HISTORY_FILE)
