The `trap' in bash scripts

trap_test1.sh

#!/bin/bash

trap "echo TRAP!!; exit" SIGTERM SIGINT SIGHUP

for (( i=0; i<5; i=i+1 ))
do
    echo $i
    sleep 1
done

trap_test2.sh

#!/bin/bash

function clean_up {
	echo CLEAN UP!!
	exit
}

trap clean_up SIGTERM SIGINT SIGHUP

for (( i=0; i<5; i=i+1 ))
do
	echo $i
	sleep 1
done

clean_up

trap_test3.sh

#!/bin/bash

function clean_up {
	echo CLEAN UP!!
}

trap "clean_up;exit" SIGTERM SIGINT SIGHUP

for (( i=0; i<5; i=i+1 ))
do
	echo $i
	sleep 1
done

clean_up