Erwtimata sxetika me firewalls

[V13]

On Friday 21 November 2003 12:23, Athanasios Sidiropoylos wrote:
> To trexw me tail -f /var/log/messages |grep TTL | ./fire
> O logos pou exw to grep einai oti den exw balei akoma kanena elenxo
> esoterika tou programatos gia na filtrarei ta axrista dedomena. To
> erwtima einai.... Giati ka8isterei xaraktiristika na tiposei ta dedomena
> pou prepei na tiposei. Mazobonte kamia 5-10 grames kai tis tiponei
> mazemenes sxedon. Yparxei periptosh na ka8isterei pano apo 15 lepta h
> host (pou kalite gia na kanei resolve to hostname apo opou erxete h
> prospa8ia sindeshs) na dosei apotelesma ??

Ofeiletai sto buffering toy stdout poy ginetai apo tin grep...

Dokimase ta eksis gia na katalabeis ti akribos ginetai:

( for a in 1 2 3 4 5 6 7 ; do echo "aa - $a" ; sleep 1s ; done ) | \
strace grep aa

kai:

( for a in 1 2 3 4 5 6 7 ; do echo "aa - $a" ; sleep 1s ; done ) | \
strace grep aa | \
(while read a ; do echo $a ; done)

(prosekse ta read()/write() )

Afaik ofeiletai kathara sto buffering poy ginetai apo tin glibc (kai oxi mono) 
se oti exei na kanei me ta i/o streams... 

> Sidhropoulos A8anasios
<<V13>>