if (@ARGV == "clean"){ print "cleaning up dirs"; clean(); }

##</code><code>##

if($ARGV[0] eq "clean") { # eq, not ==, for strings
  print "cleaning up dirs";
  clean();
}

##</code><code>##

sub clean_handler
{
  print "cleaning up dirs";
  clean();
}

sub make_handler
{
  print "making project";
  make();
}

# ...

##</code><code>##

my %cmds = (
  'clean' => \&clean, # reference to the subroutine 'clean'
  'make'  => \&make,  # reference to 'make'
  # ...
);

##</code><code>##

my $cmd = $cmds{$ARGV[0]}; # get the coderef
&$cmd();                   # call it