The problem domain seems only to be limited to numbers between one and ten. Forget push :) Just use an array as a boolean vector.

if ( $test[$guess]++ ){
  print "Duplicate\n";
}
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I'm really confused at this point, my instructor told me to get all the guessing and put them in an array so are you saying I should use push to add onto the @allguess array each time the user enters a number. As you can see I'm very new to this, the other problem I'm having is using the grep function to see if the number has been guessed.

1. I don't understand the intent of your first sentence here. Are you objecting that the PM solution offered (seems to you) to vary from your instructor's directions? If so, trust choroba's trouble-shooting. Push (see also next graf) allows you to add new elements to an array. When inside a loop, assigning a value to the array REPLACES whatever was in the array on the last iteration of the loop.
2. Perhaps your instructor mentioned using your command line to obtain local help;
   

   C:\> perldoc -f push
   or
   C:\> perldoc -f grep

There are many more sources of help local to your computer. See, for instance, perldoc perldoc and many others.

If you didn't program your executable by toggling in binary, it wasn't really programming!

I'm really confused at this point, my instructor told me to get all the guessing and put them in an array so are you saying I should use push to add onto the @allguess array each time the user enters a number.

There is no put function, see perldoc -f push

$ perl -MData::Dump -e " @a = 1; dd\@a; @a = 2; dd\@a ";
[1]
[2]

$ perl -MData::Dump -e " push @a, 1;  dd\@a; push @a, 2; dd\@a ";
[1]
[1, 2]
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For future reference, perlintro, brian's Guide to Solving Any Perl Problem, CGI Help Guide , Troubleshooting Perl CGI scripts , Re^8: How to use wxHtmlEasyPrinting (On debugging, verify everything, talk to teddybear ... and links and links , Tutorials: Perl documentation documentation, Searching Perl Documentation