The save command is used to store the entire router configuration in a backup file. The file is shown in the /file submenu. It can be downloaded via ftp to keep it as a backup for your configuration.
To restore the system configuration, for example, after a /system reset, it is possible to upload that file via ftp and load that backup file using load command in /system backup submenu.
load name=[filename] – Load configuration backup from a file
To save the router configuration to file test:
[admin@MikroTik] system backup> save name=test
Configuration backup saved
[admin@MikroTik] system backup>
To see the files stored on the router:
[admin@MikroTik] > file print
# NAME TYPE SIZE CREATION-TIME
0 test.backup backup 12567 sep/08/2004 21:07:50
To load the saved backup file test:
[admin@MikroTik] system backup> load name=test
Restore and reboot? [y/N]: y
(from mikrotik dot com)