Programming Perl, 4th Edition

Debugger Options

The debugger has numerous options that you can set with the O command, either interactively, from the environment, or from an init file.

recallCommand, ShellBang

The characters used to recall a command or spawn a shell. By default, both are set to !.

pager

Program to use for output of pager-piped commands (those beginning with a | character). By default, $ENV{PAGER} will be used. Because the debugger uses your current terminal characteristics for bold and underlining, if the chosen pager does not pass escape sequences through unchanged, the output of some debugger commands will not be readable when sent through the pager.

tkRunning

Runs under the Tk module while prompting (with ReadLine).

signalLevel, warnLevel, dieLevel

Set the level of verbosity. By default, the debugger leaves your exceptions and warnings alone because altering them can break correctly running programs.

To disable this default safe mode, set these values to something higher than 0. At a level of 1, you get backtraces upon receiving any kind of warning (this is often annoying) or exception (this is often valuable). Unfortunately, the debugger cannot distinguish fatal exceptions from nonfatal ones. If dieLevel is 1, then your nonfatal exceptions are also traced and unceremoniously altered if they came from evaled strings or from any kind of eval within modules you’re attempting to load. If dieLevel is 2, the debugger doesn’t care where they came from: it usurps your exception handler and prints out a trace, ...