The ls (list directory) command
Covered in this video: the `ls` command to list a directory's contents.
ls with no flags: just list the names of the non-hidden files
ls -l (lowercase l): list the files with more information, such as whether the file is a directory, the file size, when a file was modified, etc.
ls -al : list all the files including the hidden files, which start with a period.
ls -alrt : list all the files including hidden files in the long format, reversed by time (i.e., the files that are most recent are listed last)