Web Standards Programmer's Reference: HTML, CSS, JavaScript®, Perl, Python®, and PHP

D.2. Perl Symbolic Debugger Commands

Start the debugger with the Perl -d command line argument. Specifying a script on the command line will start the debugger with that script. The debugger supports the commands in the following table.

Command	Use
h	Prints out a help message.
T	Prints a stack trace.
s	Single-steps forward.
n	Single-steps forward around a subroutine call.
RETURN (key)	Repeats the last s or n debugger command.
r	Returns from the current subroutine.
c [ line ]	Continues until line, breakpoint, or exit.
p expr	Prints expr.
l [ range ]	Lists a range of lines. range may be a number, a subroutine name, or one of the following formats: start-end, start+amount. (Omitting range lists the next window.)
w	Lists window around current line.
-	Lists previous window.
f file	Switches to file.
l sub	Lists the subroutine sub.
S	List the names of all subroutines.
/pattern/	Searches forward for pattern.
?pattern?	Searches backward for pattern.
b [ line [ condition ]]	Sets breakpoint at line for the specified condition. If line is omitted, the current line is used.
b sub [ condition ]	Sets breakpoint at the subroutine sub for the specified condition.
d [ line ]	Deletes breakpoint at line.
D	Deletes all breakpoints.
L	Lists lines that currently have breakpoints or actions.
a line command	Sets an action for line.
A	Deletes all line actions.
< command	Sets command to be executed before every debugger prompt.
> command	Sets command to be executed before every s, c, or n command.
V [ package [ vars ]]	Lists all variables or specified vars ...