Validating files and directories

[irenezerafa]

I am using the following commands to validate a file or directory.

if [[ ! -f "$fl" && ! -d "$fl" ]]; then
printf '%s\n' "$fl: File or Directory does not exist"
fi

But have noticed that I can use -e to see if there's something by that name, 
instead of separately testing -f and -d.
Yet I am getting confused between using -a and -e.