-f file
       Tells last to use a specific file instead of /var/log/wtmp.

-num   This is a count telling last how many lines to show.

-n num The same.

-t YYYYMMDDHHMMSS
       Display the state of logins as of the specified time.  This is useful, e.g., to  determine  easily
       who  was  logged  in  at a particular time -- specify that time with -t and look for "still logged
       in".

-R     Suppresses the display of the hostname field.

-a     Display the hostname in the last column. Useful in combination with the next flag.

-d     For non-local logins, Linux stores not only the host name of the remote host but its IP number  as
       well. This option translates the IP number back into a hostname.

-F     Print full login and logout times and dates.

-i     This  option  is like -d in that it displays the IP number of the remote host, but it displays the
       IP number in numbers-and-dots notation.

-o     Read an old-type wtmp file (written by linux-libc5 applications).

-w     Display full user and domain names in the output.

-x     Display the system shutdown entries and run level changes.