Hi try this,

#!/usr/local/bin/perl

use CGI;

my $q = new CGI;
my $search_word = $q->param('search_word');
my @parameters = qw(hello1 hello2 hello345 gube);
@values = grep /^$search_word\d+/, @parameters;
print "@values";
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Always, mention the input clearly and ask the clear output in what output you need. And paste, the code what you have tried before and where you are struggle...