History with time/date

To see at what time the commands were executed from the bash history I can use HISTTIMEFORMAT variable, here's an example:

HISTTIMEFORMAT="%d/%m/%y %T "
history

History avoid duplicated entries

This will report a command just once

export HISTCONTROL=ignoredups:erasedups

But for a more complete list of command take a look at this:

ignorespace – lines beginning with a space will not be saved in history.
ignoredups – lines matching the previous history entry will not be saved. In other words, duplicates are ignored.
ignoreboth – It is shorthand for “ignorespace” and “ignoredups” values. If you set these two values to HISTCONTROL variable, the lines beginning with a space and the duplicates will not be saved.
erasedups – eliminate duplicates across the whole history.

as simple as (!!):

$ !!

$ ls -laR test
  # ...whatever result...
$ !ls
  # this executes last instance of the 'ls' command with whatever parameter it had