Use the command schedulerForexample, let's say you want to automatically back up your router's running configuration(in RAM) to the startup configuration (in NVRAM) every Monday night at 10 P.M.You might want to make sure that the system is preserving router changes, evenif the router losses power--and even if someone forgets to save his or her changes.The newIOS command scheduler makes this a relatively easy task. Here's how you can usekron to accomplish this.First,create a kron policy list. Essentially,this policy list serves as your "script," which lists what you wantthe router to run at a scheduled time. Here's an example:Router(config)# kron policy-list backupRouter(config-kron-policy)# cli writeRouter(config-kron-policy)# exitNext,create a kron occurrence, in whichyou tell the router when and how often you want to run this policy list (i.e., groupof commands). Here's an example:Router(config)# kron occurrence backup at 22:00 Mon recurringRouter(config-kron-occurrence)# policy-list backupThis codesets up your backup job to run every Monday night at 10 P.M. (22:00 in militarytime).Finally,verify that you've entered everything correctly by using the show command.Router# show kron scheduleKron Occurrence Schedulebackup inactive, will run again in 2 days 22:03:46 at 22:00 on MonRouter# show running-configuration(truncated)kron occurrence backup at 22:00 Mon recurring policy-list backup!kron policy-list backup cli write(truncated)You mightbe wondering why I used the writecommand instead of the copyrunning-configuration startup-configuration commands. While the copy run start command is interactive,the write command is not. In otherwords, write doesn't prompt to verifywhat you want to do. It's important to remember that the Cisco IOS CommandScheduler doesn't allow any interactive commands.Know your limitationsAnotherthing to look out for is that kron hasmore limitations than its Windows or UNIX counterparts. For example, you canonly use privileged-mode commands with kron;it doesn't allow any Global or Interface configuration commands. This isbecause it executes each command separately.Inaddition, it doesn't allow you to edit the list of commands once you've enteredthem. Therefore, you should test the command sequence before entering it. If acommand in the sequence fails, the router will delete that sequence of commandsand not run it again.Some ofthese limitations may be due to the fact that the command scheduler's primarydesign appears to be to allow Cisco routers to contact Cisco's CNS server torequest an automatic upgrade. While this is a good use for the commandscheduler, you can also use it for a number of other handy tasks.Fonte: http://www.techrepublic.com/article/schedule-commands-with-cisco-ios-kron/You mightbe wondering if you could use kron toreboot the router. While it's a good idea to use the command scheduler if youwant to reboot your router on a regularly scheduled basis, you can perform aone-time delayed reboot using reload at.... with less complexity.Additionaluses for kron include clearing aninterface on a daily schedule, clearing the internal log, and showing therouting table at set intervals and sending it to a log.In somecases, you may want to log the failure or success of your commands. To do so, youcan use the debug command. Forexample, to view all kron debugging, usedebug kron all. (You can also use morespecific kron debug commands.)Once you'veenabled debugging, send logging output to the router's system buffer or to asyslog server. In that log, you'll find the command output and whether thecommands succeeded