Is there a way to configure dbx to treat a blank command as a repeat of the last command?

In gdb, if I just hit return, it repeats the last command. Is there a way to configure Sun/Oracle/Solaris dbx to do likewise?

You can get that behavior by enabling "gdb mode" in dbx.

(dbx) gdb on
(dbx) step
stopped in main at line 4 in file "t.c"
    4       printf("world");
(dbx) 
step
stopped in main at line 5 in file "t.c"
    5       printf("!");
(dbx) 
step
stopped in main at line 6 in file "t.c"
    6       printf("\n");
(dbx) 
step
helloworld!
stopped in main at line 7 in file "t.c"
    7   }

Here is the help for gdb mode from the latest dbx.

(dbx) help gdb
gdb (command)
gdb on | off
Use `gdb on' to enter the gdb command mode under which  dbx will understand
and accept gdb commands. To exit  the gdb command mode and return to the dbx
command mode,  enter "gdb off". Please note that the dbx commands will  not
be accepted while in gdb command mode and vice versa.  All debugging settings
such as breakpoints are preserved  across different command modes. The
following gdb commands are not supported in the current release:
        - commands      - define
        - handle        - hbreak
        - interrupt     - maintenance
        - printf        - rbreak
        - return        - signal
        - tcatch        - until