Why does Python's readline.read_history_file not work from a script, but work interactively?

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                          I asked over on Stack Overflow, but this seems a problem specific to Mac OS X as the error does not happen on other OS (ubuntu for example). 

https://stackoverflow.com/q/42637680/447830  repeated below:

So. I own the file named ~/.osc_history, as shown below:

    $ w
    17:53  up  3:15, 5 users, load averages: 1.30 1.17 1.10
    USER     TTY      FROM              LOGIN@  IDLE WHAT
    kyma     console  -                14:39    3:14 -
    kyma     s001     -                17:20       - w
    
    $ ls -l ~/.osc_history 
    -rw-r--r--  1 kyma  staff  13 Mar  6 17:41 /Users/kyma/.osc_history
    
    $ ls -lO ~/.osc_history 
    -rw-r--r--  1 kyma  staff  - 13 Mar  6 17:41 /Users/kyma/.osc_history

The header in the file is correct:

    $ cat ~/.osc_history 
    _HiStOrY_V2_

From the interactive prompt, the following code runs fine:

    $ python
    Python 2.7.10 (default, Jul 30 2016, 19:40:32) 
    [GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.34)] on darwin
    Type "help", "copyright", "credits" or "license" for more information.
    >>> import os.path
    >>> import readline
    >>> histfile = os.path.join(os.path.expanduser("~"), ".osc_history")
    >>> histfile
    '/Users/kyma/.osc_history'
    >>> readline.read_history_file(histfile)
    >>> ^D
However, when I attempt to run the following, which I've called "yeuch.py"...

    #!/usr/bin/env python
    # -*- coding: utf-8 -*-
    
    import readline                 # Command line history
    import os.path
    
    histfile = os.path.join(os.path.expanduser("~"), ".osc_history")
    if not os.path.isfile(histfile):     # If there's no history file...
        empty = open(histfile, "a")      # ... create an ALMOST empty one...
        empty.write("_HiStOrY_V2_\n")    # ... with the special header line
        empty.close()
    readline.read_history_file(histfile) # Read history from previous sessions
    readline.set_history_length(1000)    # Default length was -1 (infinite)

...I see:


    $ python yeuch.py
    Traceback (most recent call last):
      File "yeuch.py", line 14, in 
        readline.read_history_file(histfile) # Read history from previous sessions
    IOError: [Errno 1] Operation not permitted

What the heck's going on? (I hope I'm not overlooking some stupid typo multiple times and am not a readline code expert enough to spot the error myself.)

                        

Asked by Ubuntourist (141 rep)

Mar 7, 2017, 12:58 AM
Last activity: Mar 8, 2025, 11:05 PM

Why does Python's readline.read_history_file not work from a script, but work interactively?

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