DB<1> w $t
  DB<2> c
Watchpoint 0:   $t changed:
    old value:  ''
    new value:  '14'
main::(dbt.pl:4):       print "$t\n";
  DB<2> c
14
Watchpoint 0:   $t changed:
    old value:  '14'
    new value:  '15'
main::(dbt.pl:6):       print "$t\n";
  DB<2> c
15
Watchpoint 0:   $t changed:   <<<<< the bane of my existence 
    old value:  '15'
    new value:  '42'
main::blah(dbt.pl:12):    print "$t\n";
  DB<2> c
42
Watchpoint 0:   $t changed:  <<<<< just more bane
    old value:  '42'
    new value:  '15'
main::(dbt.pl:8):       print "$t\n";
  DB<2> c
15
Watchpoint 0:   $t changed:
    old value:  '15'
    new value:  ''
Debugged program terminated.