man ps – process status

-O         is preloaded "-o"
-c         different scheduler info for -l option
-f         does full listing
-j         jobs format
-l         long format
-o         user-defined format
-y         do not show flags; show rss in place of addr
O          is preloaded "o" (overloaded)
X          old Linux i386 register format
j          job control format
l          display long format
o          specify user-defined format
s          display signal format
u          display user-oriented format
v          display virtual memory format
--format   user-defined format