bash one-liners with multiple pipes

[G. Matthew Rice]

Henry Spencer <henry-lqW1N6Cllo0sV2N9l4h3zg at public.gmane.org> writes:
> What you *can* do, possibly at some cost in convenience, is try to roll
> all the output processing into a single program.  In particular, note that
> awk can do anything that grep and sed can do, so it might be possible (if
> a little cumbersome) to just do "tail | awk".

It doesn't solve the buffering problem but:

         tail -f /some/log | awk '$7 !~ /\.(gif|png|css|jpg)/ {
                 sub("&requestUrl=.*", "", $7);
                 print $1, $7
                }'

Should do it and it fixes a potential bug in his earlier example.
The bug being that the first field [$1] is probably IP addresses but could
also be domain names [such as i.am.a.gif.com ;)].

Even with fflush in awk, I still get the buffering.

However, there's a bigger potential problem.  Is his version of tail going to
notice when his log file gets truncated and/or moved out of the way?
Something to test for, at least.

Regards,
-- 
g. matthew rice <matt-s/rLXaiAEBtBDgjK7y7TUQ at public.gmane.org>                            starnix inc.
phone: 905-771-0017 x242                        thornhill, ontario, canada
http://www.starnix.com              professional linux services & products
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