#!/bin/bash

###
rundots() { ( trap 'exit 0' SIGUSR1;  while : ;  do echo -ne '.' >&2; sleep 0.2; done) &  dotpid=$!; }
###
stopdots() { kill -USR1 $dotpid; wait $dotpid; trap EXIT; }
###
startdots() {
echo -e "\nExecuting function >>>> $(tr [a-z] [A-Z] <<< "${FUNCNAME[ 1 ]}") <<<<<"
              echo -ne "---->>Script executing, please wait"
              rundots; trap "stopdots" EXIT; return 0;
sleep 0.3}

###
main1() {
startdots
echo -e "display space usage" > /tmp/shell_script.log
sleep 4
du -sh * >> /tmp/shell_script.log
stopdots
}

main2() {
startdots
echo -e "list files," >> /tmp/shell_script.log
sleep 4
ls -lsrt >> /tmp/shell_script.log
stopdots
echo -e "\n\n*********** END OF THE BASH SCRIPT ************"
}

### call functions
main1
main2