c:\test>perl -de1

Loading DB routines from perl5db.pl version 1.32
Editor support available.

Enter h or `h h' for help, or `perldoc perldebug' for more help.

main::(-e:1):   1
  DB<1> p 'huhu'
huhu
  DB<2> $a //= 'fred'

  DB<3> p $a
fred
  DB<4> x $a
0  'fred'
  DB<5>