viper-repeat-from-history-key

viper-repeat-from-history-key is a variable defined in `viper-macs.el'.
Its value is

f12

Documentation:
Prefix key for accessing previously typed Vi commands.

The previous command is accessible, as usual, via `.'. The command before this
can be invoked as ` 1', and the command before that, and the command
before that one is accessible as ` 2'.
The notation for these keys is borrowed from XEmacs. Basically,
a key is a symbol, e.g., `a', `\1', `f2', etc., or a list, e.g.,
`(meta control f1)'.

You can customize this variable.