sub log    { ... }
sub create { ... }

my %commands = (
   log    => \&log,
   create => \&create,
   ...
);

local $_ = $command;
if (/^(\w+)/ && $commands{$1}) {
   &{$commands{$1}}();
} else {
   # Error
}

# Alternative:
#
# local $_ = $command;
# if (/^(\w+)\s+(.*)/ && $commands{$1}) {
#    &{$commands{$1}}($1, $2);
# } else {
#    # Error
# }