When you enter command into Cisco iOS it immediately becomes active in the running configuration.

But if you reboot your router, and haven’t saved your configuration, it is deleted.

If some commands were entered, to have them saved to ther configuration:

copy running-config startup-config

show running-config

show startup-config

erase startup-config

reload

returns:

Proceed with reload? [confirm]System configuration has been modified.
Save? [yes/no]: n