Customizing the Debugger

You can do some customizing by setting up a .perldb file with initialization code. When it starts up, the debugger reads and processes this file. For instance, you can set up aliases like these:

$DB::alias{'len'} = 's/^len(.*)/p length($1)/'; $DB::alias{'stop'} = 's/^stop (at|in)/b/'; $DB::alias{'ps'} = 's/^ps\b/p scalar /'; $DB::alias{'quit'} = 's/^quit\b.*/exit/';

After the configuration file has been processed, the debugger consults the environment variable PERLDB_OPTS and parses its contents as arguments to the O opt=val debugger command.

While any options can be set in PERLDB_OPTS, the following options can only be specified at startup. If you want to set them in your configuration file, call &parse_options(<">opt=val<">).

• TTY
• The TTY to use for debugging I/O.
• noTTY
• If set, goes in NonStop mode. On an interrupt, if TTY is not set, it uses the value of noTTY or /tmp/perldbtty$$ to find the TTY using Term::Rendezvous. The current variant is to have the name of the TTY in this file.
• ReadLine
• If false, a dummy ReadLine is used so that you can debug ReadLine applications.
• NonStop
• If true, no interaction is performed until an interrupt.
• LineInfo
• File or pipe to print line number information to. If it's a pipe, then a short, emacs-like message is used.

For example, if you create the following .perldb file:

&parse_options("NonStop=1 LineInfo=db.out"); sub afterinit {
 $trace = 1;
}