On Mon, 2007-04-23 at 00:06 +0000, Tyler Smith wrote: > On 2007-04-22, bilbo <[EMAIL PROTECTED]> wrote: > > 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 -200 mylog | grep 'smtg' | sed -n 's/end/notend/p' > > > > There is only one difference between these two lines - the first > extracts the last 10 lines of mylog, the second extracts the last > 200. The data you want is apparently not in the last 10 lines of > mylog.
Tyler, look at what "tail -f" it means (basically):
-f, --follow[={name|descriptor}]
output appended data as the file grows; -f, --follow, and
--follow=descriptor are equivalent
Which mean it will sit watching the file/file-descriptor for appended
output and stay attached "forever" until broken out of.
I've used it for years as part of my "watch for certain things in the
logs" scripts.
--
greg, [EMAIL PROTECTED]
Novell's Directory Services is a competitive product to Microsoft's
Active Directory in much the same way that the Saturn V is a competitive
product to those dinky little model rockets that kids light off down at
the playfield. -- Thane Walkup
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