问BASH -我怎样才能跟踪执行？比如第一次和第二次运行忽略了什么？

EN

#!/bin/bash
mkfifo pipe;
mkfifo pipe1;
ps aux | grep Java.jar | awk '{print $2}' | xargs kill -9;
sleep 1;

#
# Question on this:
# only one time it execute / its my application boot process
# - this is only one time on system startup
#
##############################################################
export DISPLAY=:0.0 && java -cp Java.jar main.Boot &

#
# second time this following should always execute
# This is my software kernel, which crash often 
# on the fly i restart it
#
while true; do cat /var/jpeg1.jpeg >> pipe; done
while true; do cat /var/jpeg2.jpeg >> pipe1; done
export DISPLAY=:0.0 && java -cp Java.jar main.Desktop &