調試器命令在perl中不工作

Question

我正在學習perl調試器。我寫了一段代碼並運行調試器。要打印更多的行，我已經發出命令1作爲'DB<1> 1'，但沒有任何事情發生。以下是代碼

package Inventory_item; 
    sub new { 
    } 

package Pen; 
    @ISA = (Inventory_item); 

    sub new { 
    } 

package Color; 
    print("Executing Color statements\n"); 
    $colors{"blue"} = "Die Lot 13"; 
    $colors{"red"} = "Die Lot 5"; 

    sub new { 
    } 

package main; 
    print("Executing main statements\n"); 

我執行命令爲'perl -d debug.txt'。然後按1的調試命令，但沒有發生

Answer 1

檢查l源上市（不1），c，並s逐句通過代碼，

List/search source lines:    Control script execution: 
    l [ln|sub] List source code   T   Stack trace 
    - or .  List previous/current line s [expr] Single step [in expr] 
    v [line] View around line   n [expr] Next, steps over subs 
    f filename View source in file   <CR/Enter> Repeat last n or s 
    /pattern/ ?patt? Search forw/backw r   Return from subroutine 
    M   Show module versions  c [ln|sub] Continue until position 
Debugger controls:      L   List break/watch/actions 
    o [...]  Set debugger options  t [expr] Toggle trace [trace expr] 
    <[<]|{[{]|>[>] [cmd] Do pre/post-prompt b [ln|event|sub] [cnd] Set breakpoint 
    ! [N|pat] Redo a previous command  B ln|*  Delete a/all breakpoints 
    H [-num] Display last num commands a [ln] cmd Do cmd before line 
    = [a val] Define/list an alias  A ln|*  Delete a/all actions 
    h [db_cmd] Get help on command   w expr  Add a watch expression 
    h h   Complete help page   W expr|* Delete a/all watch exprs 
    |[|]db_cmd Send output to pager  ![!] syscmd Run cmd in a subprocess 
    q or ^D  Quit      R   Attempt a restart 
Data Examination:  expr  Execute perl code, also see: s,n,t expr 
    x|m expr  Evals expr in list context, dumps the result or lists methods. 
    p expr   Print expression (uses script's current package). 
    S [[!]pat]  List subroutine names [not] matching pattern 
    V [Pk [Vars]] List Variables in Package. Vars can be ~pattern or !pattern. 
    X [Vars]  Same as "V current_package [Vars]". i class inheritance tree. 
    y [n [Vars]] List lexicals in higher scope <n>. Vars same as V. 
    e  Display thread id  E Display all thread ids. 
For more help, type h cmd_letter, or run man perldebug for all docs.