my %filetype = (
  'c'    => \&create_c,
  'bash' => \&create_bash, 
  'perl' => \&create_perl_script,
  'pl'   => \&create_perl_script,
  'pm'   => \&create_perl_module,
);

sub create_c {
  my $filename = shift;
  # stuff for creating a c file
}

sub create_bash {
  my $filename = shift;
  # stuff for creating a bash script
}

...

print  "What kind of file do you want to create?\n";
printf "Supported file types: %s\n", join ', ', sort keys %filetype;

# ask user for desired filetype -> $type
# ask user for desired filename -> $name

if (exists $filetype{$type}) {
  # this calls the function that is stored in the hash
  # e.g. create_bash($filename)
  $filetype{$type}->($name);
}
else {
  die "Sorry, file type '$type' is not supported.\n";
}