These parameters ask the server to list files and folders in specific ways or with specific information. They are case sensitive, and can be used in groups such as -rtaF. Always type the filter with a minus sign at the beginning. Here are a few examples;
-a Displays hidden files along with unhidden files; hidden files have a '.' as the first character in the filename.
-l (ell) List in long format, giving mode, number of links, owner, group, size in bytes, and time of last modification for each file.
-r Reverse the order of sort to get descending lists.
-t Time-sorted, most recent first.
-R Recursively look into sub-directories.
-C Displays the files in a columnar format.
-F Displays a '/' at the end of subdirectories.
-L If the argument is a symbolic link, list the file or directory to which the link refers rather than the link itself.