$ tree -F
.
├── file1.txt
├── parent_dir1/
│   ├── child_dir/
│   ├── file2.txt
│   └── file3.txt
└── parent_dir2/
    └── child_dir2/
        └── file4.txt

4 directories, 4 files
$ tree -FL 1 | grep -v /$
.
├── file1.txt

2 directories, 1 file

$ tree -FL 3 | grep -v /$
.
├── file1.txt
│   ├── file2.txt
│   └── file3.txt
        └── file4.txt

4 directories, 4 files