Dan's idea doesn't quite work:

#!/usr/bin/env python class flushfile(file): def __init__(self, f): self.f = f def write(self, x): self.f.write(x) self.f.flush() import sys sys.stdout = flushfile(sys.stdout) print "foo" 

The result:

Traceback (most recent call last): File "./passpersist.py", line 12, in <module> print "foo" ValueError: I/O operation on closed file 

I believe the problem is that it inherits from the file class, which actually isn't necessary. According to the docs for sys.stdout:

stdout and stderr needn’t be built-in file objects: any object is acceptable as long as it has a write() method that takes a string argument.

so changing

class flushfile(file): 

to

class flushfile(object): 

makes it work just fine.

Dan's idea doesn't quite work:

#!/usr/bin/env python class flushfile(file): def __init__(self, f): self.f = f def write(self, x): self.f.write(x) self.f.flush() import sys sys.stdout = flushfile(sys.stdout) print "foo" 

The result:

Traceback (most recent call last): File "./passpersist.py", line 12, in <module> print "foo" ValueError: I/O operation on closed file 

I believe the problem is that it inherits from the file class, which actually isn't necessary. According to the documentation for sys.stdout:

stdout and stderr needn’t be built-in file objects: any object is acceptable as long as it has a write() method that takes a string argument.

so changing

class flushfile(file): 

to

class flushfile(object): 

makes it work just fine.

Dan's idea doesn't quite work:

#!/usr/bin/env python class flushfile(file): def __init__(self, f): self.f = f def write(self, x): self.f.write(x) self.f.flush() import sys sys.stdout = flushfile(sys.stdout) print "foo" 

The result:

Traceback (most recent call last): File "./passpersist.py", line 12, in <module> print "foo" ValueError: I/O operation on closed file 

Dan's idea doesn't quite work:

#!/usr/bin/env python class flushfile(file): def __init__(self, f): self.f = f def write(self, x): self.f.write(x) self.f.flush() import sys sys.stdout = flushfile(sys.stdout) print "foo" 

The result:

Traceback (most recent call last): File "./passpersist.py", line 12, in <module> print "foo" ValueError: I/O operation on closed file 

I believe the problem is that it inherits from the file class, which actually isn't necessary. According to the docs for sys.stdout:

stdout and stderr needn’t be built-in file objects: any object is acceptable as long as it has a write() method that takes a string argument.

so changing

class flushfile(file): 

to

class flushfile(object): 

makes it work just fine.