sar output seems to change when piped to grep
Can someone please help explain this...
Hi, Not at all - The Codewarrior binaries are not in a format the GNU tools understand. Try to look into the libraries with the binutils tools of the m68k cross-tool package...
I'm trying to measure bandwidth in-out of a linux box using sar.
If I run sar -n DEV 1 3, I should get 3 readings, separated by a second...
Results below (I've just included the transmit and receive columns).
01:49:55 PM IFACE rxbyt-s txbyt-s 01:49:56 PM lo 0.00 0.00 01:49:56 PM eth0 394.00 970.00 01:49:56 PM eth1 0.00 0.00 01:49:56 PM sit0 0.00 0.00
I built openvpn-2.0.7 on a Red Hat ES 4 machine. I can connect to it with the OpenVPN GUI from Windows laptops. I...
01:49:55 PM IFACE rxbyt-s txbyt-s 01:49:56 PM lo 0.00 0.00 01:49:56 PM eth0 394.00 970.00 01:49:56 PM eth1 0.00 0.00 01:49:56 PM sit0 0.00 0.00
01:49:55 PM IFACE rxbyt-s txbyt-s 01:49:56 PM lo 0.00 0.00 01:49:56 PM eth0 394.00 970.00 01:49:56 PM eth1 0.00 0.00 01:49:56 PM sit0 0.00 0.00
I'm only interested in the eth0 interface, so I thought
sar -n DEV 1 3 grep eth0
would give me what I want. However, the just by grepping, the transmit and receive amounts seem to have gone down to a fraction of what sar previously told me:
01:50:16 PM eth0 110.00 254.00 01:50:17 PM eth0 110.00 254.00 01:50:18 PM eth0 110.00 254.00
Can someone please explain why this should happen? I thought the pipe would make no difference to the data coming into it. Surely I am just filtering the data to get the eth0 containing lines only?
Thanks for advice.
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