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Welcome the the Batch Renamer by Babus:
This script renames all of the files of a user-specified type, into a specific format 
	(e.g ./rename.sh txt ==> renames all of the ".txt" files of the current directory
	as follows: YYYYMMDD_001.txt, YYYYMMDD_002.txt etc.)
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The program can be run as follows:

1) ./rename.sh --help
	prints this page
2) ./rename.sh [--verbose] [--dry-run] ext
	
	ext:    This is the type of file that the script works with. In can be any combination of letters. In case this arguments does not consist of only letters,
		an error message is printed and the script terminates. (exit code:2)
		If there are no ".txt" files inside the current directory, a message is printed and the script exits. (exit code:0)
	
	verbose: This mode gives the user some more info about what is happening during execution. More specifically, it gives information about creation 
                 of log directory and log files.

	dry-run: This is the "safe-mode" of the script. Instead of actually renaming files, it just prints messages about what would be exeuted.

	The script can be run with no complementary argument, one complementary argument, or two complementary arguments in no specific order. In any case, 
	the complementary arguments, if any, must be followed by the user-specified extension.

	Below, you can find all of the valid executions (pdf extension). In any other case an error message will be printed and the script will terminate (error code:2)
		1) ./rename.sh pdf
		2) ./rename.sh --dry-run pdf
		3) ./rename.sh --verbose pdf
		4) ./rename.sh --dry-run --verbose pdf
		5) ./rename.sh --verbose --dry-run pdf
	The script also prints an error message and exits(exit code:2) in case of typing errors:
		1) ./rename.sh -verbose pdf
		2) ./rename.sh --dry-urn pdf
		3) ./rename.sh --verbose .pdf

Under the hood:

	1) The script firstly parses the arguments to ensure correct input, as described above.
	2) A welcome message is printed.
	3) A log directory is created, if it does not already exist. (./logs)
	4) A log file for the current day is created, if it does not already exist (./logs/YYYYMMDD_log.txt)
	5) The script parses all of the files of the specified type that exist inside the working directory (only on this level, not recursively)
	6) It separates the file in 2 lists. Those that already have a name of the correct format, and those who don't
	7) The script only renames the files that are not named in the correct format.
	8) Everything that is executed inside the script is written in today's log file (./logs/"today's_date"_log.txt)

In order to understand how the script works and test it, you can run "./tester.sh"
	This script creates some txt files:
		0-10 files that preceed YYYYMMDD, such as 11111.txt, (pre-files) 
		0-10 of the correct format, such as 20251110_001.txt, (files)
		0-10 files that come after YYYYMMDD, such as 33333.txt, (post-files).
	After the creation of the files, it runs the original "./rename.sh" script to start renaming and everything is written
	inside today's log. After the renaming of the files is completed, all of the .txt files are deleted. 
	This process is repeated 100 times.

	In corner cases:
		1) 0 pre-files 			2) 0 files 				3) 0 post-files 	
		4) 0 pre-files and 0 files	5) 0 pre-files and 0 post-files 	6) 0 files and 0 post-files
		7) 0 pre-files 0 files 0 post files
		
	the script works properly.
	
	!It is advised that you run the tester in this directory for educational and testing purposes. When ready to use, you can copy the "rename.sh"
	inside your desired folder and start renaming!!!

For more information, contact me: panosx9797@gmail.com
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