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There're lots of print function (python 2.7) in my program. Is there any way I can add a few lines then all the output can be redirected to stderr? What I want is python codes but not linux pipeline.

For example, my program is like:

print 'hello world'

I would like to add some codes like:

redirect_output_to_stderr() print 'hello world'

Then all the output can be redirected to stderr.

I know print >> sys.stderr, 'hello world' can achieve my goal, but is it any way that can prevent from modifying the existed codes?

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  • 1
    The only way to do that without modifying the code is to use a shell's redirection commands. Commented Apr 7, 2013 at 8:42
  • Oh, I guess what I need is preventing from modified the existed print functions. Thank you for mentioned that :) Commented Apr 7, 2013 at 8:45

3 Answers 3

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20

In python 2.7 you can do:

import sys print >> sys.stderr, "To stderr."

Or you can import the behavior from 3.x:

from __future__ import print_function import sys print('To stderr.', file=sys.stderr)
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8

Do this in your method:

import sys sys.stdout = sys.stderr
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2 Comments

Or maybe don't, god this is horrible advice.
@ruohola Yeah, not a great thing to do in any code, even 6 years ago! But I guess this is exactly what the question was asking for ¯_(ツ)_/¯
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Redefinition of print is feature of Python 3+. However, you can change sys.stdout to std.stderr.

See: another question

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2 Comments

You can redefine print in 2.7 if you do from __future__ import print_function.
@lvc Didn't know that. Still change of stdout is shorter than function redefinition.

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