Write a shell script that lists files by modification time when called with lm and by access time when called with la.

This shell program will lists files by modification and access time, by default the script should show the listing of all files in the current directory

echo "*****************************"
if [ "$1" == "la" ];then
echo "Access time"
ls -ul | tr -s " " | cut -d " " -f 6,7,8,9
elif [ "$1" == "lm" ];then
echo "Modification time"
ls -ml | tr -s " " | cut -d " " -f 6,7,8,9
else
echo "***list of all files in current directory***"
ls -l | tr -s " " | cut -d " " -f 9
fi