working commands - day to day usage

Convert files from dos to unix for current folder
find . -type f -print0 | xargs -0 dos2unix

convert files from specific folder from dos to unix.
 find /<foldername> -type f -print0 | xargs -0 dos2unix

recursive permissions for folder
chmod -R 777 *

Create a tar command
tar cvf test.tar * 
where test.tar is file name to be created.

Extract the tar

tar xvf test.tar
where test.tar is file to be extracted.
Windows : Recursive deletion of files.
Delete Files of Specific Extension using Command Prompt