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I'm running a Python3 script on the terminal, and on my terminal it writes out a lot of print() statements that I added, as well as output from libraries I'm using.

I wish to save the output in a file, so I run the script like this.

python3 myscript.py > logfile.txt

Everything I print() from within Python now goes into the file as I want, instead of being printed to my terminal.

However, within this script I'm also using the ftputil library to download files, and some output from ftputil still shows on the terminal where I ran the script. So now the output of my program is split in 2 parts, which makes it less useful. 

download-ftp.py:160: DeprecationWarning: `use_list_a_option` will default to `False` in ftputil 4.x.x with ftputil.FTPHost(ftp_addr, ftp_user, ftp_pw) as ftp_host:

What is needed to make the output from ftputil also go into the file that I want?

user985366
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  • Take a look there: https://stackoverflow.com/questions/4675728/redirect-stdout-to-a-file-in-python – olinox14 Aug 21 '19 at 09:39
  • Thanks, I have seen that one and based on the top answer, I did as suggested ```A far more common method is to use shell redirection when executing (same on Windows and Linux): $ python foo.py > file``` . Might need to read the rest though. – user985366 Aug 21 '19 at 09:42
  • Yeah, I'm not sure why the `ftputil` output is not redirected but if it is pure python, changing the sys.stdout and sys.stderr should work... – olinox14 Aug 21 '19 at 09:45
  • I think I might need to redirect stderr as well, as explained here https://askubuntu.com/questions/625224/how-to-redirect-stderr-to-a-file – user985366 Aug 21 '19 at 11:20
  • ftputil maintainer here. :-) Normally there shouldn't be any shell output from ftputil. What's the output you're seeing that might come from ftputil? – sschwarzer Aug 21 '19 at 20:42
  • @sschwarzer ```download-ftp.py:160: DeprecationWarning: `use_list_a_option` will default to `False` in ftputil 4.x.x with ftputil.FTPHost(ftp_addr, ftp_user, ftp_pw) as ftp_host:``` The rest of the output was actually from something else, I noticed. But this warning came from ftputil as far as I can tell. – user985366 Aug 22 '19 at 11:31

1 Answers1

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You're right, this deprecation warning is from ftputil.

ftputil uses the Python warnings module to show this warning. The warnings module not only outputs warnings (by default to stderr), but also offers ways to control which warnings are actually shown (see The Warnings Filter and Temporarily Suppressing Warnings).

You can suppress the ftputil warning with

import warnings

import ftputil


with warnings.catch_warnings():
    warnings.simplefilter("ignore", category=DeprecationWarning)
    ftp_host = ftputil.FTPHost(host, user, password)
...

If you really want the deprecation warning in your log file, you can use the methods that others have suggested in the comments. Here's an example:

import sys

import ftputil           


old_stderr = sys.stderr
sys.stderr = sys.stdout
try:
    ftp_host = ftputil.FTPHost(host, user, password)
finally:
    sys.stderr = old_stderr
sschwarzer
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