The command line interface is an integral part of using linux and unix systems. Many pieces of software are available only in command line or provide additional functionality. The command line interface also provides the ability to script actions and pipe or connect commands together.
Enter in shell commands with arguments to see a detailed explanation. The explainshell.com site provides a great way to learn and test commands.
Most commands have the following format:
command -options arguments
List all files in current directory
Prints full path of current directory to the terminal
Change directory to path specified as argument
Working with Files:
cp file_copy_from file_copy_to
copy files and directories
mv file_from file_to
move or rename files and directories
remove files and directories