history subcommand for dbx: Display commands in a history list

Usage notes

The history subcommand displays the commands in the history list. As each command is entered, it is appended to the history list. A mechanism for history substitution is provided through the exclamation (!) operator. The allowable forms are !! for a previous command, !n for the nth command, and !string for the previous command that starts with string. The number of commands retained and displayed is controlled by the dbx internal variable $historywindow.