[Linux Shell]if-else example

# ifelse_exam.sh script is used to check if the input string is a current directory
#! / bin / bash

#Test if the user input is empty, and then determine whether the file exists in the current directory

if ["$ 1"]
then
         echo "What you input is not null"
         if [-e "$ 1"]
         then
                 echo "The file $ 1 is existence!"
         else
                 echo "The file $ 1 is not existence!"
         fi
else
         echo "What you input is null!"
fi 

[Linux Shell]if-else example