perl的debugger模式

湯姆大叔：The service I ran was in perl -d and I traced through some of the requests to see where they were blowing up.

$ man perldebug
( also see $ man perldebtut )

$ perl -d xxx.pl
進入  DB<1>
n =>執行下一行
p print "test"; =>執行一行程式，亦可在此改變變數
h => 指令說明書
R =>重頭開始

Max: 可以看變數執行的過程變化跟設定中斷點跟測試等等
Max: 不過 perl -d 也只適合單機的程式
Max: 網頁的話要加工
Max: 不實用

Harry的debugger模式重點：

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.