How can I disable the new history feature in Python 3.4?

Question

Since upgrading to Python 3.4, all interactive commands are logged to ~/.python_history. I don't want Python to create or write to this file.

Creating a symlink to /dev/null does not work, Python removes the file and recreates it. The documentation suggests to delete the sys.__interactivehook__, but this also removes tab-completion. What should be done to disable writing this history file but still preserve tab-completion?

Additional details:

• Distro: Arch Linux x86_64
• readline 6.3-3
• python 3.4.0-2

Answer 1

Another ~/.pythonrc solution:

import readline
readline.write_history_file = lambda *args: None

Answer 2

As of Python 3.6, you can use readline.set_auto_history to disable this:

import readline
readline.set_auto_history(False)

Answer 3

This works for me.

Creating ~/.pythonrc file:

import os
import atexit
import readline

readline_history_file = os.path.join(os.path.expanduser('~'), '.python_history')
try:
    readline.read_history_file(readline_history_file)
except IOError:
    pass

readline.set_history_length(0)
atexit.register(readline.write_history_file, readline_history_file)

Then export it:

export PYTHONSTARTUP=~/.pythonrc

Answer 4

To prevent Python from writing ~/.python_history, disable the hook that activates this functionality:

import sys
# Disable history (...but also auto-completion :/ )
if hasattr(sys, '__interactivehook__'):
    del sys.__interactivehook__

If you would like to enable tab-completion and disable the history feature, you can adapt the site.enablerlcompleter code. Write the following code to ~/.pythonrc and set export PYTHONSTARTUP=~/.pythonrc in your shell to enable it.

import sys
def register_readline_completion():
    # rlcompleter must be loaded for Python-specific completion
    try: import readline, rlcompleter
    except ImportError: return
    # Enable tab-completion
    readline_doc = getattr(readline, '__doc__', '')
    if readline_doc is not None and 'libedit' in readline_doc:
        readline.parse_and_bind('bind ^I rl_complete')
    else:
        readline.parse_and_bind('tab: complete')
sys.__interactivehook__ = register_readline_completion

Answer 5

My current solution (for recent enough versions of Python 3) prevents default use of ~/.python_history but leaves the possibility of explicit writing of the history to a given file (using readline.write_history_file(filename) or readline.append_history_file(...)) is to have the following in one's PYTHONSTARTUP file:

import readline
import time

readline.add_history("# " + time.asctime()) # prevent default use of ~/.python_history
readline.set_history_length(-1) # unlimited

It has the pleasant (for me) side effect labeling any explicitly written history with the startup time of the interpreter. It works because of the fix for bug 5845 which can be seen here.

Answer 6

Until it's fixed in some way in Python itself you can do this on UNIX systems:

rm ~/.python-history
mkdir ~/.python-history
sudo chattr +i ~/.python-history || sudo chflags simmutable ~/.python-history

After that you will be getting

Error in atexit._run_exitfuncs:

IsADirectoryError: [Errno 21] Is a directory

every time you terminate a python shell. Exit status will still be 0.

Notice that if you leave it as file you need to create and make immutable another file, ~/.python_history

Answer 7

Put the following in a file and set PYTHONSTARTUP to it (or call the file sitecustomize.py and make it accessible from the PYTHONPATH)

import readline
import atexit
import sys

sys.__interactivehook__()
atexit.unregister(readline.write_history_file)

This way you'll still have access to tab-completion and previous history, but the commands you enter won't be added to the history file.

Answer 8

Here's my method (which turned out to be basically a more reliable and pythonic version of berdario's method). It only disables writing to .python_history, but not reading from it if it exists, or appending new lines to the current instance's history. I recommend saving it as site-packages/sitecustomize.py, because site is the module that both writes to .python_history and imports sitecustomize if it exists, although naming it something else and pointing to it with PYTHONSTARTUP works too.

import sys
oldhook = getattr(sys, '__interactivehook__', None)
if oldhook:
    def newhook():
        import readline, atexit
        oldhook()
        atexit.unregister(readline.write_history_file)
    sys.__interactivehook__ = newhook

update: what i did for 3.7, specific to my system, not pep8:

import rlcompleter,readline as r,sys
def f():r.parse_and_bind('tab:complete');r.read_init_file()
sys.__interactivehook__=f