You were using last() gratuitously, and had too many "}". If you want to allow guesses for multiple numbers, add a loop around creating a new value for $secret, and re-engineer exit conditions.

Corrected and formatted code :

#!\usr\bin\perl -w
my $secret= int(1+ rand 100);
while(1){
  print"please enter a number:";
  chomp(my $guess=<STDIN>);
  if($guess=~/quit|exit|^\s*$/i){
    print"Sorry,the number was $secret.\n";
    last;
  }elsif($guess>$secret){
    print "Too large,try again.\n";
    ##last;
  }elsif($guess==$secret){
    print"that is it.\n";
    last;
  }else{
    print"Too small,try again.\n";
  }
}
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Update:Un-commented "first last" - see hbo's note below.