.
|-- dir1
| |-- a
| | |-- file1.txt (60GB)
| | `-- file2.txt
| |-- b
| | `-- file3.txt (20GB)
| `-- c
| `-- file4.txt
`-- dir2
|-- a
| |-- file1.txt (10GB)
| `-- file6.txt
|-- b
| |-- file3.txt (50GB)
| `-- file8.txt
`-- c
|-- file10.txt
`-- file9.txt.
|-- dir1
`-- dir2
|-- a
| |-- file1.txt (60GB)
| |-- file2.txt
| `-- file6.txt
|-- b
| |-- file3.txt (20GB)
| `-- file8.txt
`-- c
|-- file4.txt
|-- file9.txt
`-- file10.txtmkdir test
cd test
mkdir dir1 dir1/a dir1/b dir1/c
dd if=/dev/zero of=dir1/a/file1.txt bs=1M count=60
dd if=/dev/zero of=dir1/a/file2.txt bs=1M count=1
dd if=/dev/zero of=dir1/b/file3.txt bs=1M count=20
dd if=/dev/zero of=dir1/c/file4.txt bs=1M count=1
mkdir dir2 dir2/a dir2/b dir2/c
dd if=/dev/zero of=dir2/a/file1.txt bs=1M count=10
dd if=/dev/zero of=dir2/a/file6.txt bs=1M count=1
dd if=/dev/zero of=dir2/b/file3.txt bs=1M count=50
dd if=/dev/zero of=dir2/b/file8.txt bs=1M count=1
dd if=/dev/zero of=dir2/c/file9.txt bs=1M count=1
dd if=/dev/zero of=dir2/c/file10.txt bs=1M count=1tree . 
% tree -h test
test
├── [4.0K] dir1
│ ├── [4.0K] a
│ │ ├── [ 60M] file1.txt
│ │ └── [1.0M] file2.txt
│ ├── [4.0K] b
│ │ └── [ 20M] file3.txt
│ └── [4.0K] c
│ └── [1.0M] file4.txt
└── [4.0K] dir2
├── [4.0K] a
│ ├── [ 10M] file1.txt
│ └── [1.0M] file6.txt
├── [4.0K] b
│ ├── [ 50M] file3.txt
│ └── [1.0M] file8.txt
└── [4.0K] c
├── [1.0M] file10.txt
└── [1.0M] file9.txt
8 directories, 10 files% cp -lrf test/dir{1/*,2} && rm -rf test/dir1/*% tree -h test
test
├── [4.0K] dir1
└── [4.0K] dir2
├── [4.0K] a
│ ├── [ 60M] file1.txt
│ ├── [1.0M] file2.txt
│ └── [1.0M] file6.txt
├── [4.0K] b
│ ├── [ 20M] file3.txt
│ └── [1.0M] file8.txt
└── [4.0K] c
├── [1.0M] file10.txt
├── [1.0M] file4.txt
└── [1.0M] file9.txt
5 directories, 8 files