Maybe this one is common knowledge, but it caught me off guard. And it might
save somebody some time.
Assume we have a logfile. To watch it on your terminal, you
could type 'tail -f logfile'.
To filter the output, you could use 'tail -f logfile | grep foo'.
All as expected. But you want more filtering, so you type:
'tail -f logfile | grep foo | grep bar'
And get no output at all, even though there are log entries that contain both
foo and bar!
It turns out that a pipe has a buffer of 4096 characters and is holding the
data. To make it work, you need:
'tail -f logfile | grep --line-buffer foo | grep bar'
and now you get the filtered output as expected.
--Brian
--
I think my life is fuller because I realize
that I don't know what I'm doing.
I'm delighted with the width of the world!
---Richard Feynman
Brian Daniels [EMAIL PROTECTED]
http://www.eviloverlord.net
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