output redirect - how to get reatime streaming using tail -f

Question

I am using runnit to run a python process on ubuntu. I redirect the output of the program to a log file.

exec /usr/bin/python /home/ubuntu/workspace/monitor.py >> /tmp/monitor.out 2>&1

I then use

tail -f /tmp/monitor.out

to have a look at what is going on.

Howerver, it output is not streaming. Always behind, some times by a few minutes. Its not a lot of output.

How do I get realtime streaming?

This sounds like an issue with redirected output being buffered. Maybe one of these links would be helpful? http://stackoverflow.com/questions/2753350 http://stackoverflow.com/questions/2055918 — ashastral, Jul 24 '12 at 17:08
Glad I could help. I'll post that as an answer since it seems to be correct. — ashastral, Jul 24 '12 at 17:31

score 1 · Accepted Answer · edited May 23 '17 at 10:34

1

The output is probably being buffered. Put sys.stdout.flush() somewhere at the end of the script's loop to write the buffer to disk immediately. (See here for more information)

edited May 23 '17 at 10:34

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answered Jul 24 '12 at 17:31

ashastral

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output redirect - how to get reatime streaming using tail -f

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