A common task in unix-like operating systems is creating an archive of many files or directories in a single file. The tar command is one option for archiving and has many options and can do many things.
In a simple example, you can create a file called archive.tar of all the files and subdirectories in the current directory with the following command:
tar cf archive.tar *
Note that this file is different from a zip archive commonly used in Windows environments because it is uncompressed.
You can also preserve permissions, owner and group by adding the p parameter.