Today i faced a situation in which i have to mail Cisco Nexus “Show tech-support” to Cisco TAC, the output was very long as it was taking 15 minutes to display the entire output on the screen and i was not able to copy the entire content in one go, i searched the internet and cisco  however not any easy method i have found, after struggling initially at last i figured out a simple way, the way was so simple that i was really amazed.

For this you need to have Putty installed on your computer, it is free and can be downloaded from here , then you need to adjust some settings in putty before connecting to your device, for this open the putty console, under Session click the tab Logging, the default option selected is None, so change it to “All session Output” and under Log File Name click the tab Browse and choose a location on your computer, then again click to Session, under session click Default Settings and Save it.

Now type the ip address of the destination device and select the port and connect to the device, in the exec-mode of the cisco device prompt, type “terminal length 0” so that the whole command can be executed in one shot. Run whatever command you want to run in my case it is “show tech-support” and take copy of that command into the file mentioned by you under the putty. The complete output is now  in your file. Also in case of running “Show tech-support” on your device do take a backup-copy of the running-config first and then save the config before executing “Show tech-support”.Enjoy :)