デバッグ

スクリプトの厳格化

曖昧な記述に対してエラーや警告を出させることで、バグの入り込む余地を減らします。これによりデバッガを使う以前に問題を発見できます。

strict

安全ではない記述をエラーにできます。

#!/usr/bin/perl
use strict;
strict - perldoc.perl.org strict - 安全ではない構文を制限する Perl プラグマ - perldoc.jp

warnings

use warnings;
warnings - perldoc.perl.org

参考

起動オプションによる制御

Usage: C:\Perl\bin\perl.exe [switches] [--] [programfile] [arguments]
  -0[octal]         specify record separator (\0, if no argument)
  -a                autosplit mode with -n or -p (splits $_ into @F)
  -C[number/list]   enables the listed Unicode features
  -c                check syntax only (runs BEGIN and CHECK blocks)
  -d[:debugger]     run program under debugger
  -D[number/list]   set debugging flags (argument is a bit mask or alphabets)
  -e program        one line of program (several -e's allowed, omit programfile)
  -E program        like -e, but enables all optional features
  -f                don't do $sitelib/sitecustomize.pl at startup
  -F/pattern/       split() pattern for -a switch (//'s are optional)
  -i[extension]     edit <> files in place (makes backup if extension supplied)
  -Idirectory       specify @INC/#include directory (several -I's allowed)
  -l[octal]         enable line ending processing, specifies line terminator
  -[mM][-]module    execute "use/no module..." before executing program
  -n                assume "while (<>) { ... }" loop around program
  -p                assume loop like -n but print line also, like sed
  -s                enable rudimentary parsing for switches after programfile
  -S                look for programfile using PATH environment variable
  -t                enable tainting warnings
  -T                enable tainting checks
  -u                dump core after parsing program
  -U                allow unsafe operations
  -v                print version, patchlevel and license
  -V[:variable]     print configuration summary (or a single Config.pm variable)
  -w                enable many useful warnings
  -W                enable all warnings
  -x[directory]     ignore text before #!perl line (optionally cd to directory)
  -X                disable all warnings
perl --help

これらの起動オプションは、スクリプトで指定するならば、

#!/usr/bin/perl -W

のように記述します。

cオプション

実行時にcオプションを指定すると、構文チェックを行えます。

perl -c programfile

Wオプション

すべての警告を有効にします。

dオプション

デバッガでプログラムを実行します。

List/search source lines
コマンド 説明
l [ln|sub] List source code
- or . List previous/current line
v [line] View around line
f filename View source in file
/pattern/ ?patt? Search forw/backw
M Show module versions
Debugger controls
コマンド 説明
o [...] Set debugger options
<[<]|{[{]|>[>] [cmd] Do pre/post-prompt
! [N|pat] Redo a previous command
H [-num] Display last num commands
= [a val] Define/list an alias
h [db_cmd] Get help on command
h h Complete help page
|[|]db_cmd Send output to pager
q or ^D Quit
Control script execution
コマンド 説明
T Stack trace
s [expr] Single step [in expr]
n [expr] Next, steps over subs
<CR/Enter> Repeat last n or s
r Return from subroutine
c [ln|sub] Continue until position
L List break/watch/actions
t [expr] Toggle trace [trace expr]
b [ln|event|sub] [cnd] Set breakpoint
B ln|* Delete a/all breakpoints
a [ln] cmd Do cmd before line
A ln|* Delete a/all actions
w expr Add a watch expression
W expr|* Delete a/all watch exprs
![!] syscmd Run cmd in a subprocess
R Attempt a restart
Data Examination
コマンド 説明
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.

参考

参考

参考

関連ページ

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