Displaying online usage messages
You can look up detailed usage descriptions or you can display brief summaries of the syntax and options of commands and utilities.
If you want a detailed description of a utility, see the Utilities Reference. But if you just want a quick reminder of the syntax and options, you can display the utility's online usage message by invoking the use command (it's similar to man in UNIX and Linux). For example, to display the message for more, type:
If you request usage for a command, and the command either doesn't have an executable in the current path or doesn't contain usage message records, use displays an error message. For more information, see use in the Utilities Reference — or simply type use use.