a bash script to demonstrate bash input and output

progress.sh

function readCommand(){
   lastCommand=$1
   read -t.1 -n1 c;
   if [ "$c" = "p" ]
   then
     printf "\n\r"; 
     return 0
   fi
   if [ "$c" = "g" ]
   then
     printf "\n\r"; 
     return 1
   fi
  return $lastCommand
}


function spin(){
 	for i in / - \\ \| ;
        do 
            printf "\r$i"; 
            sleep .1;
        done
}

function countUp(){
    currentCount=$1
    return `expr $currentCount + 1`
}

function counter(){
    countUp $count
    count=$?
    printf "\r$count"
    sleep .1;
}

command=1
count=0
while : 
do 
   if [[ $command == 1 ]]
   then
      spin
   fi
   readCommand $command
   command=$?
done