Maybe I'm missing something, but this behavior of x and p looks very odd to me:

lanx@nc10-ubuntu:~$ perl -de0
 
Loading DB routines from perl5db.pl version 1.3
Editor support available.
 
Enter h or `h h' for help, or `man perldebug' for more help.
 
main::(-e:1):    0
  DB<1> p print "lula"
1lula
  DB<2> x print "horst"
0  1
  DB<3> p print "lula"
1horstlula
  DB<4> p print "lula"
1lula
  DB<5> p print "lula"
1lula
   
 ...
   
  DB<11> x print "horst"
0  1
  DB<12> x print "horst"
0  1
  DB<13> x print "horst"
0  1
  DB<14> p print "lula"
1horsthorsthorstlula

[download]

Cheers Rolf

UPDATE: improved example code.

UPDATE2: INTERPRETATION: Sleeping about it brought some insight about the fundamental differences between a debugger and a shell resp. REPL. I'm mostly using the debugger as a shell, expecting to get every line's output directly after typing. A debugger OTOH shouldn't alter the standard behavior of perl in order to find errors, and this naturally includes buffering.

While it's strange that p flushes and x doesn't, the wanted REPL behavior can be achieved by setting $| to 1.

In reply to Debugger Bug? by LanX

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