you are aware that RHEL5.0 is not even supported by redhat
the current in the old legacy support 5 series is RHEL5.11
5.0 is 10 minor versions and 8 YEARS out of date
5.0 was released in March of 2007
also seeing as this IS redhat
you did buy the REQUIRED support contract 8 years ago ??????
have you read through the redhat documentation for the old 5 series
as for the "date" command
please read the manual for that command
the list of commands is there