npm comes with a full set of commands, and each of the commands takes a
similar set of arguments.
In general, all commands on the command object take an array of positional
argument strings. The last argument to any function is a callback. Some
commands are special and take other optional arguments.
All commands have their own man page. See man npm-<command> for command-line
usage, or man 3 npm-<command> for programmatic usage.