script uses "cgrep" command

anhtt · 09-28-2007, 01:17 PM

I wrote a script that have a following command:

tail -f 070928.APX | cgrep -E "AC FAILURE ALARM|LOW VOLTAGE ALARM"

The command didn't run.But when I use the only command:
tail -f 070928.APX | grep "AC FAILURE ALARM" or
tail -f 070928.APX | grep "LOW VOLTAGE ALARM"
Two above commands ran.

What happended ? Did the problem happend to "tail" or "cgrep" command ?
And after finishing the script, how to end the "tail" process.

Please help me to solve this.
Thanks

raskin · 09-28-2007, 02:11 PM

cgrep is a more powerful grep replacement, but in this case just ordinary egrep will do.

anhtt · 09-29-2007, 11:01 AM

Thanks. Now it's ok.
But I have one more problem.
When I store the result of the command by " > /tmp/ac & ".
The file /tmp/ac was empty. For example:

tail -f 070929.APX | cgrep -E "AC FAILURE|LOW VOLTAGE" > /tmp/ac &

raskin · 09-29-2007, 12:07 PM

Maybe it waits for end of input; I do not remember behavior of grep inside a long pipe, but some core text tool had problems with it.