What happened to “write memory” IOS command in Cisco Nexus 7000 Series Switch?

When configuring Cisco Catalyst Switches, I quite often use “write memory” command to save my configuration rather than using “copy running-configuration startup-configuration” Cisco IOS command. Other day I was saving my running configuration to the startup configuration in a Cisco Nexus 7000 Series Switch in the usual way ” wri mem”. But I got the following error

VDC-Admin-DC-AGG1# write memory
^
% Invalid command at ‘^’ marker.
VDC-Admin-DC-AGG1#

Now Cisco Nexus 7000 Series switch won’t support the “write memory” command. Rather you need to use the “copy running-configuration startup-configuration” to save your configuration. One more difference I figured out between Cisco IOS and NX-OS is the missing of “write memory” command.

VDC-Admin-DC-AGG1#
VDC-Admin-DC-AGG1# write ?
erase  Destroys the configuration on persistent media

VDC-Admin-DC-AGG1# write

Now the time has come for me better start using “copy running-configuration startup-configuration” command in NX-OS based Cisco switches.