rpinoit version of ls shell command

Available options:

MANDATORY:

• -l List in long format.
• -R Recursively list subdirectories encountered.
• -a Include directory entries whose names begin with a dot.
• -r Reverse the order of the sort.
• -t Sort by time.

BONUS:

• -A List all entries except for "." and "..".
• -d Directories are listed as plain files (not searched recursively).
• -g List in long format, but omit the user id.
• -o List in long format, but omit the group id.
• -p Write a slash (`/') after each filename if that file is a directory.
• -f Output is not sorted. This option turns on the -a option.
• -S Sort files by size
• -c Use time when file status was last changed for sorting (-t) or long printing (-l).