use Safe ;

  my $PACK = new Safe ;

  $PACK->deny(qw(
wantarray vec warn 
grepstart grepwhile mapstart mapwhile enteriter iter enterloop leaveloop unstack
last next redo goto
readline rcatline getc read formline enterwrite leavewrite
print sysread syswrite send recv
eof tell seek sysseek readdir telldir seekdir rewinddir
bless sprintf prtf crypt
tie untie dbmopen dbmclose
sselect select pipe_op sockpair
getppid getpgrp setpgrp getpriority setpriority localtime gmtime
rand srand atan2 sin cos exp log sqrt reset
chroot syscall dump exit die warn fork lock threadsv
  )) ;
  
  ## I use select to turn of output:
  my $sel = select(NULL) ;
  
  $PACK->reval(q`
  ## your code that need to be safe....
  `) ;
  
  ## select again the previous output:
  select($sel) ;