Does SQL*Plus provide the help pages for its commands? Is there a way to access the help text from the SQL*Plus prompt, like this text for STARTUP?
I tried
SQL> man startup
SP2-0734: unknown command beginning "man startu..." - rest of line ignored.
SQL> startup -help
SP2-0714: invalid combination of STARTUP options
SQL> startup --help
SP2-0714: invalid combination of STARTUP options
SQL>