You can also use the archive feature and rollback changes: http://www.ciscozine.com/reload-in-x-why-dont-you-rollback-or-replace-the-configuration/
But relo in x is the easiest and fastest way to do it. It has saved me several times.
This is a much better way of controlling versions then just copying running config to Flash. You can have the router automatically back itself up.
R5(config)#archive ! you need to set the archive up first
R5(config-archive)#path ! you have to set the path where the files will go
R5(config-archive)#path ?
ftp: Write archive on ftp: file system
http: Write archive on http: file system
https: Write archive on https: file system
pram: Write archive on pram: file system
rcp: Write archive on rcp: file system
scp: Write archive on scp: file system
tftp: Write archive on tftp: file system
R5(config-archive)#path tftp://10.30.0.62/R5
R5(config-archive)#time-period ? !the router can automatically back itself up
<1-525600> Number of minutes to wait between archive creation
R5(config-archive)#time-period 10080! one a week
archive
path tftp://10.30.0.62/R5
time-period 10080
archive config ! forced the archive. This should be done before anyone makes any changes to the router, especially clients that are far from us.
!!
R5#c
Enter configuration commands, one per line. End with CNTL/Z.
R5(config)#host not-R5! made some changes
not-R5(config)#^Z
not-R5#b tftp://10.30.0.62/R5-1 list time 10! restoring the old config, and list the changes
!!Timed Rollback: Backing up to tftp://10.30.0.62/R5-4
This will apply all necessary additions and deletions
to replace the current running configuration with the
contents of the specified configuration file, which is
assumed to be a complete configuration, not a partial
configuration. Enter Y if you are sure you want to proceed. ? [no]: y
Loading R5-1 from 10.30.0.62 (via FastEthernet0/1): !
[OK - 3135 bytes]
!Pass 1
!List of Commands:! what it changed back
no hostname not-R5
hostname R5
end
Total number of passes: 1
Rollback Done
R5#! back to original config
R5#show archive config differences ! this will show you what is different in the running config vs. what is in the archived config. Answers the question “what has changed on the router”.
Contextual Config Diffs:
-username remove-me password 0 askdjhfr80
Could you quote the relevant parts from your link in case it is removed in the future? Please see [answer] for more details. – Burgi – 2016-10-10T17:38:10.953