grep | sed do not function inline?

[bilbo <bilbo@l-arrache.com>]

Hi all,

Recently I faced a strange behaviour of the Linux commands. I have a
log file which contains a lot of information. I wanted to extract some
informations out of it. But when I tried to

tail -f mylog | grep 'smtg' | sed -n 's/end/notend/p'

no output could be found. Which was quite surprising since the
following tests did their job without any problem:

tail -f mylog | grep 'smtg'
tail -f mylog | sed -n 's/end/notend/p'
tail -200 mylog | grep 'smtg' | sed -n 's/end/notend/p'

So, of course, to achieve this result I simply went for perl. But can
anyone tell me what is the reason why this didn't work?

Thanks,
Tudi.