snippet grinder I needed to run the debugger on a long-running process, and the conditional breakpoint required was too hairy for my poor brain to figure out. After a bit of spelunking in <tt>perldoc perldebug</tt> and <tt>perldoc DB</tt> I came up with the code below. There are a few things to be aware of: <ol> <li>Note the <tt>-d</tt> switch on the shebang line. This will run the program under the debugger.</li> <li>Using <tt>-d</tt> will by default stop execution at the first executable statement. To start the program immediately without have to wait for a person to hit the 'r' key and press enter, the environment variable <tt>PERLDB_OPTS</tt> should be set to <tt>nonstop</tt>. Hence, in a Bournish shell, the program should be run with <tt>PERLDB_OPTS=nonstop myprogram myarg1 myarg2...</tt> </li> <li>Setting <tt>$DB::single</tt> to 1 will cause the debugger to take over control at the beginning of the next statement. The documentation warns that this variable should be considered read-only, but setting it doesn't appear to have any ill effects that I could see.</li> </ol> In my real-life example, the setting of $DB::single involved opening sockets to remote machine and database lookups, but in essence was doing nothing more than the example below. It might make more sense to say <tt>$DB::single = maybe_breakpoint($foo, $bar, $rat,...)</tt> and encapsulate the mess in a subroutine. Also note that XML::SAX::PurePerl is really, really slow under the debugger. Do not adjust your terminal, it will respond... eventually <tt>:)</tt> <CODE> #! /usr/bin/perl -wd use strict; for my $step( 0..9 ) { print "$step\n"; $DB::single = 1 if $step == 5; } </CODE>