tail -f in python with no time.sleep

Question

I need to emulate \"tail -f\" in python, but I don\'t want to use time.sleep in the reading loop. I want something more elegant like some kind of blocking read, or select.se

Answer 1

When reading from a file, your only choice is sleep (see the source code). If you read from a pipe, you can simply read since the read will block until there is data ready.

The reason for this is that the OS doesn't support the notion "wait for someone to write to a file". Only recently, some filesystems added an API where you can listen for changes made to a file but tail is too old to use this API and it's also not available everywhere.