getting ./coundown 5 to countdown from 5

Question

I have a file named countdown on my computer and I am trying to get it to countdown from what ever the user puts in.

for example ./countdown 5 would cause a 5 second timer to start outputting a "." every second and prints done after 5 seconds.

./countdown 10 would cause a 10 second timer to start outputting "." every second and prints done after 10 seconds.

here is my code, how can i read what the user inputs

t=$((5))
while [ $t -gt 0 ]; do
   echo -ne "."
   sleep 1
   : $((t--))
done
echo "done"

Answer 1

Just change t=$((5)) to t=$1, which will assign the first argument to t.