su --command 'read -n 1 -s key; if [ "$key" == "g" ]; then su; fi;'
echo -n "W"
sleep 0.09
echo -n "e"
sleep 0.09
echo -n "l"
sleep 0.09
echo -n "c"
sleep 0.09
echo -n "o"
sleep 0.09
echo -n "m"
sleep 0.09
echo -n "e"
sleep 0.09

Welcome

root@myuser:~#

otheus@otheus-VirtualBox ~ $ ( while true; read x; do echo $x; done; ) &
[1] 2841
otheus@otheus-VirtualBox ~ $

[1]+  Stopped                 ( while true; read x; do
    echo $x;
done )

start_worker &

while jobs %- &>/dev/null; do
   read -n 1 -s -t 1 key
   # test key
   if [[ $key == q ]]; then
      kill -1 %-
      break
   fi
fi
wait

read -n1

array=(W e l c o m e)
buf=0
while pgrep "inputproc" > /dev/null; do
    echo -n ${array[buf]}
    ((buf++))
    sleep 0.09
done
#Insert any commands you want to run afterwards here...

./mainscript & ./inputproc