make_nested_structure.sh

#!/usr/bin/env bash
# before:
#    $> tree .
#    .
# 
#    0 directories, 0 files````
#
# 
# after:
#    $> tree .
#    .
#    ├── test1
#    │   └── test3
#    │       └── test4
#    └── test2
#        └── test3
#            └── test4
# 
#    6 directories, 0 files
mkdir test1;
mkdir test2;
find . -mindepth 1 -maxdepth 1 -execdir bash -c "cd "{}";mkdir test3; cd test3; mkdir test4; echo `pwd`" \;