You can abbreviate a _GDBN__ command to the first few letters of the command
name, if that abbreviation is unambiguous; and you can repeat certain
-GDB commands by typing just @key{RET}. You can also use the @key{TAB}
+_GDBN__ commands by typing just @key{RET}. You can also use the @key{TAB}
key to get _GDBN__ to fill out the rest of a word in a command (or to
show you the alternatives available, if there's more than one possibility).