how to use kill SIGUSR2 in bash?
kill, linux, shell
Solution
`SIGUSR2` is architecture depended and can have a value out of `31`, `12` or `17`. This is described in `man 7 signal`. You'll have to find out which value is appropriate for your system. Usually this is done by having a look into:
/usr/include/asm/signal.h
On my system - Ubuntu 12.04 AMD 64 - it has a value of `12`:
#define SIGUSR2 12
Once you know the proper numeric value for `SIGUSR2` on your system, you can send this signal using:
kill -SIGNO PID
# In this case
kill -12 PID
Problem
I use iptraf to monitor the network traffic in linux, and the shell command is(make iptraf running in background): ``` iptraf -s eth0 -f -B -L ./traffic.dat ``` if I want to get the result, I have to stop iptraf first, so I use the shell command: ``` kill -SIGUSR2 $pid ``` however, I could not stop iptraf if I move these shell commands into a bash script file(net.sh), and I get an error: ``` kill: SIGUSR2: invalid signal specification ``` I use 'kill -l' in the script file(net.sh), and I find there is no parameter which name is SIGUSR2. and I would get nothing if I 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 get nothing after these commands. what shoud I do if I want to get the result?