The mkdir Command
To create new directories from the command line, you will use the mkdir command. When you open a terminal window, you will find yourself in your home directory. You can check this by typing pwd which stands for "print working directory." You can list the current files in your home directory, by typing ls. Your new directory must have a different name than the existing directories, so it is a good idea to know what is already there.
To create a single directory, you will type the command mkdir new_directory. This will create a new directory with the name new_directory. If you want to create more than one directory, you can list each one after the mkdir command. For example, the command mkdir dir1 dir2 dir3 will create the directories dir1, dir2, and dir3. If you want to create a new directory within a different existing directory, you must specify the exact path to the new directory. For example, the command mkdir Pictures/new_pics issued from the home directory will create a new_pics sub directory in the Pictures directory.
The mkdir command will fail if the parent directory specified does not exist. In the example above, the command will fail if the Pictures directory does not exist. However, you can use the -p option to create the parent directories. So if the Pictures directory does not exist, you can type mkdir -p Pictures/new_pics/ to create both directories with one command.