b           Sets breakpoint on current line

b [line] [condition]
            Set a breakpoint before the given line. If a condition is
            specified, it's evaluated each time the statement is
            reached: a breakpoint is taken only if the condition is
            true. Breakpoints may only be set on lines that begin an
            executable statement. Conditions don't use "if":

                b 237 $x > 30
                b 237 ++$count237 < 11
                b 33 /pattern/i

b subname [condition]
            Set a breakpoint before the first line of the named
            subroutine. *subname* may be a variable containing a code
            reference (in this case *condition* is not supported).

b postpone subname [condition]
            Set a breakpoint at first line of subroutine after it is
            compiled.

b load filename
            Set a breakpoint before the first executed line of the
            *filename*, which should be a full pathname found amongst
            the %INC values.

b compile subname
            Sets a breakpoint before the first statement executed after
            the specified subroutine is compiled.