Linux for Networking Quick Start Cheat Sheet

Using Linux for networking completely unifies the network stack. The switch from traditional networking operating systems is easy and can be done with existing skill sets.
This handy cheat sheet is a quick reference as you learn and use NVIDIA® Cumulus® Linux. It features the most common native Linux, as well as Cumulus NVUE, commands with explanations on how to use them.

Common Linux Commands

sudo `command` Run a command in root	man `program` Display help menu for program	kill `PID` Halt process by process-id	killall `proccess_name` Halt any processes based on a name
history Display recently entered commands	sudo reboot Reboot the switch immediately	`command` -h Display commands help menu	`command` & Send command execution to the background (use “fg” to send command to the foreground)

Linux User Administration Commands

sudo adduser `username` Add a user	sudo userdel -r `username` Delete a user	sudo passwd `username` Change a user password	sudo passwd -l `username` Disable a user	id `username` Display user information
who Display all logged-in users and their activity	whoami Display the current logged-in user	su `username` Switch user	last Display last login of a user(s)	exit Logout of the current session

Linux Monitoring and Troubleshooting Commands

top View real-time CPU/memory info	free -m Show free memory in MB	ps aux Show all running processes
uptime Display uptime info	nslookup `hostname` Perform DNS lookup	ntpq -pn Perform ntp query
date Print the current date and time	tcpdump -i `interface` Collect control plane traffic from an interface	clear Clear a command-line screen
smonctl -v Show PSU/FAN/Temp information	ping `ip_address` Check connectivity status to remote IP	sudo cl-support Create an archive file for troubleshooting. A tar file will be created in the /var/support/ directory.

Working with Files and Folders

nano `file_name` Edit a text file	tree Show filesystem hierarchy	pwd Print current folder name	head -n 5 `file_name` Display top 5 lines of a file
tail -n 5 `file_name` Display last 5 lines of a file	tail -f `file_name` Follow file and disaplay new lines	mkdir `folder` Make new folder	cd `folder` Change into different folder
ls -lha List the files in the current folder	find / -name `file_name` Find file named `file_name`	find / -name `"string"` Find file_name containing `string`	chmod 777 `file_name` Change file permissions to all
mv `old_file` `new_file` Move/rename a file	cp `old_file` `new_file` Copy a file	rm `file_name` Delete a file	chown `username` `file_name` Change file ownership
grep `"string"` `file_name` Search file for a text `string`	touch `file_name` Create a new file	cat `file_name` Display a text file	`command` > `new_file` Redirect stadndard command output to a file. e.g. `ip link show > ip_addr_output`
cat `/path/file_name` \| grep `"string"` > `new_file` Filter one program’s/files output to a file. e.g. `cat /var/log/syslog \| grep kernel > syslog_kernel_output`		`command` & > `new_file` Redirect stadndard command output and Standard error to a file. e.g. `ifreload -a & > ifreload_output`

NVUE (NVIDIA User Experience) General Commands

nv list-commands List all NVUE commands	nv show `[options]` `attribute` Show system configuration	nv set `attribute` Modify system configurations
nv unset `attribute` Remove system configurations attribute	nv config `command` Manage/Apply system configurations	nv `command` -h Show command usage with all its options and attributes

System Software and Hardware Commands

sudo -E apt list `package_name` Show the list of packages based on package name (all if `package_name` not specified)	sudo -E apt-get install `package_name` Install a package from the repository	sudo -E apt-get update Update software packages to latest versions
sudo apt-cache search `string` Look for packages containing `string`	sudo systemctl `[start\|stop\|restart\|reload]` `program`.service Control current execution of a service	sudo systemctl `[enable\|disable]` `program`.service Set/unset a service to start on system boot
cat /etc/image-release Show precise software version	nv show system global Show switch global configuration	nv show platform software installed `package_name` Show a specific installed software package on the switch (all if `package_name` not specified)
nv show platform capabilities Show switch hardware information	nv show platform hardware `component_device` Show switch hardware information	nv show platform hardware component device fan Show switch PSU/FAN/Temp information

Working with Interfaces

Using Linux Commands

ip addr show `interface` Layer 2 and 3 interface status	cl-netstat Display interfaces counters	ifup `interface` Set port admin UP	ifdown `interface` Set port admin DOWN
ifreload -a Apply interface configuration changes	ip addr set `ip_address/mask` dev `interface` Set IP address and mask to an interface	ifquery -s Show ALL interface keywords	ifquery -a Show interfaces config (to be applied)
ethtool `interface` Show transceiver information	ethtool -S `interface` Show port statistics	ethtool -s `interface` speed `speed` Set physical interface's speed	ip monitor link Monitor changes to link state in real time

Using NVUE Commands

nv show interface High-level interfaces status	nv show interface `interface` Detailed interface status and counters	nv set interface `interface` link state down Administratively disable physical port
nv set interface `interface` link state up Administratively enable physical port (by default all ethernet ports are disabled)	nv set interface `interface` ip address `ip_address/mask` Set IP address to physical layer 3 port or loopback	nv set `interface` bridge domain br_default Creates a default bridge and sets physical port/s as its member
nv unset interface `interface` ip address Unset IP address from an inteface (SVI/layer 3/Lo)	nv set interface vlan `vlan_id` ip address `ip_address/mask` Create and set IP address to logical layer 3 port (SVI)	nv set interface `bond0` bond member `interface(s)` Create bond(LAG) interface and set physical member(s) into it
nv set interface `interface` link speed `speed` Set physical interface's speed	nv show interface `interface` `[attribute]` Show interface's configuration	nv set interface `interface` link breakout `breakout_options` Breakout physical interfaces according to the supported options

Important Log Files

cat /var/log/apt Logs for apt utility	cat /var/log/audit/* Logs for auditd service	cat /var/log/syslog The main system log	cat /var/log/clagd Logs status of the clagd service
cat /var/log/frr/frr.log Location of the FRRouting log (if enabled)	cat /var/log/rdnbrd.log Logs for redistribute neighbor	cat /var/log/netd.log Log file for NVUE	cat /var/log/ptmd Logs file for ptmd service
cat /var/log/switchd.log The HAL log for NVIDIA Cumulus Linux	cat /var/log/autoprovision Logs output generated by running the ZTP script		cat /var/log/dpkg.log Log file for packages added or removed using dpkg command
cat /var/log/installer/* Directory containing files related to the NVIDIA Cumulus Linux installation		dmesg (driver message) is a command that prints the message buff of the kernel

Configuration Management with NVUE Commands

nv config apply Applies the pending configuration	nv config detach Detaches the configuration from the current pending
nv config save Overwrites startup configuration with the applied configuration (writes to `/etc/nvue.d/startup.yaml`). This configuration persists after reboot.
nv config diff `revision_1` `revision_2` Compares between two configuration types (e.g. `pending` vs. `applied`)	nv config history `nvue-file` Shows applied configuration history for the revision
nv config patch `nvue-file` Updates pending configuration with a YAML file	nv config replace `nvue-file` Replaces pending configuration with a YAML file