-R -- list subdirectories recursively
-S -- sort by size
-T -- specify tab size
-U -- unsorted
-X -- sort by extension
-a -- list entries starting with .
-b -- print octal escapes for control characters
-c -- status change time
-d -- list directory entries instead of contents
-f -- unsorted, all, short list
-g -- long listing but without owner information
-h -- print sizes in human readable form
-i -- print file inode numbers
-k -- use block size of 1k
-l -- long listing
-m -- comma separated
-n -- numeric uid, gid
-o -- no group, long
-p -- append file type indicators except *
-q -- hide control chars
-r -- reverse sort order
-s -- display size of each file in blocks
-t -- sort by modification time
-u -- access time
-v -- sort by version (filename treated numerically)
-w -- specify screen width
-x -- sort horizontally