- Welcome to the Cisco Nexus 3550F Fusion Documentation
-
- Command Line Interface
- Configuration Management
- User Management
- Diagnostics
- Statistics Logging
- Configuring Ports
- Packet Capture
- Patches and Taps
- FPGA Module
- Switch Objects
- Mux Objects
- MAC Address Table
- IGMP and Multicast
- VLAN Support
- Mirror and Timestamping Fusion
- Mirror and Timestamping Fusion HPT
- Virtual Ports
- LLDP
- SNMP
- TACACS+
- Access Control
- Latency Statistics
- BGP
- Bash Shell
- Automatic Configuration
- Known Issues
Bash Shell
Version
This feature requires version 1.8.0 or later
The Cisco Nexus 3550-F Fusion (formerly ExaLINK Fusion) command line interface provides access to a bash shell, which supports many standard UNIX commands and the ability to run scripts.
Accessing the Bash shell
To access the bash shell from the CLI, use the bash
command:
admin@N3550-F> bash
ExaLINK Fusion shell
admin@N3550-F:~$
The bash
command is only available to users with the admin
role.
Directories
/media/userfs
contains the startup configuration and other files which need to persist across updates. This is the only part of the filesystem that is preserved on a firmware update./media/userfs/debug
is a temporary directory for debug dumps. Its contents does not persist across reboots./media/userfs/update
is a temporary directory for firmware updates. This also does not persist across reboots.
Note that home directories are also temporary and no user files may be placed in them. Files which need to persist should be placed in /media/userfs
.
Shell Scripting
Shell scripts should be placed in /media/userfs
or in a subdirectory and must have #!/bin/bash
or #!/bin/sh
as the first line. The executable bit will automatically be set for these files.
Using Cisco Nexus 3550-F Fusion Commands from the Shell
The Nexus 3550-F command interpreter can be accessed from the Bash shell using the cli
command. Commands can be provided to the command interpreter using the -c
argument, for example:
admin@N3550-F:~$ cli -c 'show port'
Port Status Description
---- ------ -----------
...
This is useful if you want to use unix shell commands such as grep
together with Nexus 3550-F commands, for example:
admin@N3550-F:~$ cli -c 'show port' | grep 'down'
It can also be used to run commands from shell scripts.
Python Scripting
The Nexus 3550-F has a Python interpreter installed.
admin@N3550-F:~$ python
Python 2.7.3 (default, Jun 5 2017, 12:52:39)
[GCC 4.8.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>
Bindings are provided for access to the JSON-RPC API. This can be accessed by importing the module exalink
.
>>> import exalink
This creates an exalink
object in the current namespace. Fusion JSON-RPC API calls can be accessed as methods of this object, for example:
>>> print exalink.get_ports()
Python scripts should be placed in /media/userfs
or in a subdirectory and must have #!/usr/bin/python
as the first line. The executable bit will automatically be set for these files.
Cron Jobs
The Nexus 3550-F supports cron for running user-defined tasks at scheduled times.
The Cron configuration file is called crontab. This file can be edited by running the command crontab -e
in the bash shell:
admin@N3550-F:~$ crontab -e
Note that the crontab
utility on the Nexus 3550-F is specially modified to always edit the admin user's crontab. This means any users with access to the bash shell can edit the same crontab, and that all cron jobs will run as the user admin.
Here is an example crontab for running a script every 5 minutes:
*/5 * * * * /media/userfs/hello.py
Each line consists of 5 fields followed by a command. The 5 fields specify the time and day the command is to be run. In order, they are:
- Minute (0 to 59)
- Hour (0 to 23)
- Day of month (1 to 31)
- Month (1 to 12)
- Day of week (0 to 6)
Each field can be a number, a comma-separated list (eg. 5,10,15
), or *
. The /
syntax is also supported, so for example */5
in the first field means every 5 minutes.
Use the crontab -l
command to list the current cron configuration:
admin@N3550-F:/media/userfs$ crontab -l
*/5 * * * * /media/userfs/hello.py