Startup and running config

Unanswered Question
Feb 27th, 2008

How would you see if there is a difference in the startup and running config of an IOS switch?


I have this problem too.
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lamav Wed, 02/27/2008 - 11:51


Execute a "sh start" and then a "sh run" and view the configurations side-by-side and line-by-line to see the differences.



skhirbash Wed, 02/27/2008 - 11:56

If you have saved any modification to the running-config file, then there will be no difference and therefore you won't be able to compare. Otherwise, what I would do is the following:

- sho running-config till the last line.

- copy the contents and paste to a text editor.

- reload the device

- sho startup-config

- compare each line in the startup-config file against the contents you have pasted in the text editor(which should be the running-config file).

Hope this helps.


lamav Wed, 02/27/2008 - 12:06


Why does he have to reload the device just to get the output of a 'sh run" and a "sh start"?


skhirbash Wed, 02/27/2008 - 13:56

That step is not really necessary; however, I assumed that there could be a possibility of a corrupt startup-config file and reloading the device can verify it.

lamav Wed, 02/27/2008 - 13:59

OK. I hope he reads your explanation before he submits a change control just to check the start up config. :-)

There's a suite of commands just for this:

That link is for router IOS but the commands are preset on recent switch software revs. They're "unsupported" so they don't show up in the switch documentation and therefore I can't tell you what minimum rev you need to be running. I also believe you need to be on a switch family >=3550.

Edit: I just checked my Cat6.5k (SUP2/MSFC2) and the command is not present. My Cat4.5k does have it. Bottom line is YMMV. :-)

Edit2: You also need to specify the file system where the files are that you want to diff. In your case, system:running-config and nvram:startup-config


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