Removing the content of a directory recursively [closed]

I want to delete the content of a folder without deleting a folder: all files and all sub folders with sub files. This doesn't delete anything

sudo rm -rf /folder1/*

Why not? How to get it to work?

Is this folder1 really directly in root /? You must either use relative or absolute path:

sudo rm -rf folder1/*
sudo rm -rf /full/path/to/folder1/*

Then you must remember that the wildcard is handled before sudo. If the user doesn't have permission to read contents of folder1, the wildcard returns nothing. You can test that with

sudo echo folder1/*

In that case you may

sudo bash
rm -rf folder1/*