Any reason for using "*/" in command "ls -d */" to list directories?

Question

I know there are some other ways to do the same thing, such as

ls -l | grep "^d"

or

ls -F | grep "/$"

I am just curious about the reason for adding "*/" after "ls -d". Why simply using "ls -d" not work? Is there any story or tricky stuff behind it?

Answer 1

Adding the -d flag simply instructs ls to simply list directory entries rather than their contents. The * given to ls is expanded to all the entries in the current directory, both files and dirs. So ls -d * will list all entries in this directory, without expanding the subdirectories. But if you use */, then bash expands this to only include the directories in this directory. But with just ls */, all the directories will be expanded. Adding the -d flag prevents that, and you get just the directories in this directory.