linux - how to use kill SIGUSR2 in bash? -

i use iptraf monitor network traffic in linux, , shell command is(make iptraf running in background):

iptraf -s eth0 -f -b -l ./traffic.dat 

if want result, have stop iptraf first, use shell command:

kill -sigusr2 $pid 

however, not stop iptraf if move these shell commands bash script file(net.sh), , error:

kill: sigusr2: invalid signal specification 

i use 'kill -l' in script file(net.sh), , find there no parameter name sigusr2. , nothing if use usr2 or -9.

the complete script file is:

    iptraf -s eth0 -f -b -l ./temp.txt     pid=`ps -ef | grep iptraf | grep -v grep | awk '{print $2}'`     kill -usr2 $pid     cat temp.txt 

i nothing after these commands.

what shoud if want result?

sigusr2 architecture depended , can have value out of 31, 12 or 17. described in man 7 signal. you'll have find out value appropriate system. done having into:

/usr/include/asm/signal.h  

on system - ubuntu 12.04 amd 64 - has value of 12:

#define sigusr2     12 

once know proper numeric value sigusr2 on system, can send signal using:

kill -signo pid # in case kill -12 pid