Your task is to prepare 2 shell scripts:

1. Write a script  chngnm  which will have the following syntax:

  chngnm  [-r|--recursive] [-s|--subdirectories] [-l|--lowercase|-u|-uppercase] <dir/file names...>
  chngnm  [-h|--help]
  

The goal of the script is to change names of files. The script is dedicated to
lowerizing (-l or --lowercase) file and directory names or uppercasing (-u or
--uppercase) file and directory names given as arguments. 

Changes may be done either with recursion (for all the files in subdirectories
'-s' or --subdirectories) or without it.  In recursive mode changes may affect
only regular file names  or  subdirectory names (if with '-s' or --subdirectories)
as well.  Option -h (or --help) should print help message.


2. Write additional script  chngnm_examples  to demostrate and to test chngnm
working scenarios, also to test how the script behaves when incorrect arguments
to chngnm are given.


--
Examples of correct usage:

chngnm -l File1 FILE2
chngnm -u a*
chngnm -r -u file1 dir1 dir2 dir3
chngnm -r -s -u file1 file2 dir1 dir2