whoami displays the login name corresponding to the current effective user ID. If you have used su to temporarily adopt another user, whoami will report the login name associated with that user ID. whoami gets its information from the geteuid and getpwuid library routines (see getuid and getpwnam (3C), respectively).
username data base
See attributes(5) for descriptions of the following attributes:
This command is obsolete and will be removed in a future release of Solaris. See who(1) for an alternate implementation of this command.