Timer on shell scripting

1. Operating System Lab
Course Code: CSE 324
CourseTeacher: Mr. Md. Sabab Zulfiker
Project Name: Count Down Clock in Shell Script

2. Team Name: Gladiators
Md. Ashikur Rahman
191-15-2469
Yousuf Mia
191-15-2360
Mizanur Rahman Masum
191-15-2502

3. Introduction ofTime Count Down

4. Project Source Code:
#!/bin/bash
if [ $# -lt 1 ]
then
echo "Time Needed in Seconds"
echo "Usage: $0 <seconds>"
echo "Example: $0 10"
exit 1
fi
time="$1"
start="$SECONDS"
s=1
function main(){
echo "Welcome..."
while [ $s -gt 0 ]
do
s="$((time - (SECONDS - start)))"
echo -ne "r r"
echo -ne "r$s seconds left"
sleep 1
done
echo -e "nTimes Up"
exit 0
}
main