tar cvf cs253.tar cs253
This creates a file, often called a tarball, that contains the entire cs253 folder along with any subdirectories inside it recursively. The option c stands for create, the option v for verbose and the option f for the name of the tarball to follow.
Then you can copy the tarball to another location on your system, or copy to another system or copy it to a CD or USB drive or email it to someone. Suppose you have a tarball that you want to unpack. Use the following command:
tar xvf cs253.tar
Here the option x is for extract.
If you want to list the table of contents for a tarball without extracting any files, use the t option.
tar tvf cs253.tar