[Chapter 15] 15.28 The Perl Debugger
Author: Stephen Spainhour and Valerie Quercia
Date: Fri Aug 29 18:13:41 1997

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| Chapter 15 Perl Quick Reference |

## 15.28 The Perl Debugger

The Perl symbolic debugger is invoked with perl -d.

h

  Prints out a help message.

T

  Prints a stack trace.

s

  Single steps.

n

  Single steps around subroutine call.

[RETURN]

  Repeats last s or n.

r

  Returns from the current subroutine.

c [ line ]

  Continues (until line, or another breakpoint, or exit).

p expr

  Prints expr.

l [ range ]

  Lists a range of lines. range may be a number, start-end, start+amount, or a subroutine name. If range is omitted, lists next window.

w

  Lists window around current line.

-

  Lists previous window.

ffile

  Switches to file and starts listing it.

lsub

  Lists the named subroutine.

S

  Lists the names of all subroutines.

/pattern/

  Searches forward for pattern.

?pattern?

  Searches backward for pattern.

b [ line [ condition ]]

  Sets breakpoint at line; default is the current line.

b sub [ condition ]

  Sets breakpoint at the subroutine.

d [ line ]

  Deletes breakpoint at the given line.

D

  Deletes all breakpoints.

L

  Lists lines that have breakpoints or actions.

a line command

  Sets an action for line.

A

  Deletes all line actions.

< command

  Sets an action to be executed before every debugger prompt.

> command

  Sets an action to be executed before every s, c, or n command.

V [ package [ vars ] ]

  Lists all variables in a package. Default package is main.

X [ vars ]

  Like V, but assumes current package.

! [ [-]number ]

  Re-executes a command. Default is the previous command.

H [ -number ]

  Displays the last -number commands of more than one letter.

t

  Toggles trace mode.

= [ alias value ]

  Sets alias, or lists current aliases.

q

  Quits. You may also use your EOF character.

command

  Executes command as a Perl statement.

Environment Variables |  | Other CGI Resources