Attach GDB to a spawned program matching a certain name within ~100ms

attach-gdb.pl

#!/usr/bin/env perl

use 5.12.0;
use warnings;

my $pname = $ARGV[0] // die "usage: $0 NAME\n";

for (my $i = 0;; ++$i) {
    state @pids;
    chomp(my @new_pids = `pgrep $pname`);

    if ($i and @new_pids > @pids) {
        my ($new) = grep { my $a = $_; not grep {$_ == $a} @pids } @new_pids;
        say "$new spawned! attaching gdb...\n";
        exec "gdb", "attach", $new;
    }

    @pids = @new_pids;
    select undef, undef, undef, 0.1;
}