DB<1> h >
 ?            List Perl commands to run after each prompt.
 expr        Define Perl command to run after each prompt.
> expr        Add to the list of Perl commands to run after each prompt.
 *        Delete the list of Perl commands to run after each prompt.
 DB<2> h }
 is not a debugger command.
 DB<3> h {
 db_command    Define debugger command to run before each prompt.
 ?            List debugger commands to run before each prompt.
{ db_command    Add to the list of debugger commands to run before each prompt.
 *             Delete the list of debugger commands to run before each prompt.
 DB<4> h <
 ?            List Perl commands to run before each prompt.
 expr        Define Perl command to run before each prompt.
< expr        Add to the list of Perl commands to run before each prompt.
 *                Delete the list of perl commands to run before each prompt.
 DB<5>