Cisco Nexus useful commands
I have been working with Nexus for a while and picked up some really useful commands. I use these commands on a daily basis and it saves me few minutes every now and then :)
Please let me know in comments if you know any other interesting commands to try.
1.Find out when was the last time you copied the running config to start up config.
switch(config)# feature bash-shell
switch(config)# 2020 May 12 22:49:59
switch %$ VDC-1 %$ %SECURITYD-2-FEATURE_ENABLE_DISABLE: User has enabled the feature bash-shell
switch# run bash ls -ld /var/sysmgr/startup-cfg/ascii/system.cfg
-rw-rw-rw- 1 root root 4673 May 12 22:35 /var/sysmgr/startup-cfg/ascii/system.cfg2. Create your own alias commands
The very first thing I do on a new Nexus switch is set up an alias for "wr" You can create an alias for any command you want.
switch# wr
^
% Invalid command at '^' marker.
switch# conf ter
Enter configuration commands, one per line. End with CNTL/Z.
switch(config)# cli alias name wr copy running-config startup-config
switch(config)# exit
switch# wr
[########################################] 100%
Copy complete, now saving to disk (please wait)...
Copy complete.3. Executing multiple CLI commands in one go
switch# conf t ; Interface Eth1/5 ; description packetswitch-demo
Enter configuration commands, one per line. End with CNTL/Z.
switch(config-if)# end
switch# show interface status | incl Eth1/5
Eth1/5 packetswitch-demo notconnec 1 auto auto 10g
4. Filtering show logging output
switch# show clock
22:36:23.745 UTC Tue May 12 2020
Time source is NTP
switch# show logging logfile start-time 2020 May 12 22:30:00
2020 May 12 22:30:10 switch %VDC_MGR-5-VDC_STATE_CHANGE: vdc 1 state changed to updating
2020 May 12 22:30:10 switch %VDC_MGR-5-VDC_STATE_CHANGE: vdc 1 state changed to active
2020 May 12 22:30:19 switch %ETHPORT-5-SPEED: Interface Ethernet1/1, operational speed changed to auto
switch# show logging last 2
2020 May 12 22:50:03 switch %VSHD-5-VSHD_SYSLOG_CONFIG_I: Configured from vty by cisco on console0
2020 May 12 22:50:17 switch %VSHD-5-VSHD_SYSLOG_CMD_EXEC: User:cisco executed the command:run bash5. Tracking configuration changes / Accounting
switch# conf ter
Enter configuration commands, one per line. End with CNTL/Z.
switch(config)# inter eth1/2
switch(config-if)# description DEMO
switch(config-if)# end
switch# show accounting log | incl "DEMO"
Tue May 12 22:38:37 2020:type=update:id=console0:user=cisco:cmd=configure terminal ;
interface Ethernet1/2 ; description DEMO (REDIRECT)
Tue May 12 22:38:37 2020:type=update:id=console0:user=cisco:cmd=configure terminal ;
interface Ethernet1/2 ; description DEMO (SUCCESS)
switch# show accounting log | last 2
Tue May 12 22:58:57 2020:type=update:id=console0:user=cisco:cmd=configure termin
al ;
interface Ethernet1/4 ; description diff (REDIRECT)
Tue May 12 22:58:57 2020:type=update:id=console0:user=cisco:cmd=configure termin
al ;
interface Ethernet1/4 ; description diff (SUCCESS)6. Easily generate "show tech-support" output
"show tech-support" might take a long time to show all the outputs. You can however, use the below command to create an archive file and send it over to TAC.
switch# tac-pac bootflash:showtechout.gz
Show tech detail can take more than 5 minutes to complete. Please Wait ...
switch# dir
4096 May 12 22:28:14 2020 .rpmstore/
4096 May 12 22:28:35 2020 .swtam/
1335985152 Feb 17 15:30:28 2019 nxos.9.2.3.bin
0 May 12 22:31:14 2020 platform-sdk.cmd
4096 May 12 22:29:37 2020 scripts/
5311525 May 12 22:42:44 2020 showtechout.gz <<<<<< show tech-support7. View previous and next lines from the "show" output
switch# show running-config | incl DEMO
description DEMO
switch# show running-config | grep prev 2 next 2 DEMO
interface Ethernet1/2
description DEMO
interface Ethernet1/3
switch# 8. Turning off pagination
Display all the output without stopping at the end of each page. This is particularly useful with lengthy "show run" or "show ip route" commands.
switch# show run | no-more
switch# show ip route vrf prod | no-more
9. show cli history, self-explanatory
switch# show cli history
31 22:57:15 conf ter
32 22:57:18 interface eth1/3
33 22:57:21 description test
34 22:57:23 no switchport
35 22:57:24 end
36 22:57:27 show cli history 10. Configuration difference between running-config and startup-config
switch(config)# interface eth1/4
switch(config-if)# description diff
switch(config-if)# end
switch# show run diff
*** Startup-config
--- Running-config
***************
*** 39,48 ****
--- 39,49 ----
interface Ethernet1/3
description test
no switchport
interface Ethernet1/4
+ description diff
interface Ethernet1/5
description packetswitch-demo
interface Ethernet1/611. Run CLI commands for a specific VRF without adding VRF <vrf_name> every time to the command
switch# routing-context vrf prod
switch%prod# show ip interface brief
IP Interface Status for VRF "prod"(3)
Interface IP Address Interface Status
Vlan10 10.10.10.5 protocol-up/link-up/admin-up
Vlan20 10.10.20.5 protocol-up/link-up/admin-up
Vlan30 10.10.30.5 protocol-up/link-up/admin-up 12. Embedded Logic Analyzer Module
ELAM can look inside Cisco ASIC and understand how a packet is forwarded. It can capture a packet in real-time without disruptions to performance or control-plane resources. Please check out my other blog for the full article: https://packetswitch.co.uk/cisco-embedded-logic-analyzer-module-2/
Reference
I learnt some of the tips from here: http://www.firewall.cx/cisco-technical-knowledgebase/cisco-data-center/1206-nexus-nx-os-commands-scripting-hints-and-tips.html
Thanks for reading
As always, your feedback and comments are more than welcome.