Controlling Environment Variables; Documents Listed On This Page - Cisco 7604 Configuration Manual

Chapter 3 Configuring the Router for the First Time
Modifying the Supervisor Engine Startup Configuration
The router uses the NVRAM configuration during initialization when the CONFIG_FILE environment
variable does not exist or when it is null (such as at first-time startup). If the router detects a problem
with NVRAM or a checksum error, the router enters setup mode. See the "Using the Setup Facility or
the setup Command" section on page 3-2 for more information on the setup command facility.

Controlling Environment Variables

Although the ROM monitor controls environment variables, you can create, modify, or view them with
certain commands. To create or modify the BOOT environment variable, use the boot system global
configuration command.
Refer to the "Specify the Startup System Image in the Configuration File" section in the "Loading and
Maintaining System Images and Microcode" chapter of the Configuration Fundamentals Configuration
Guide for details on setting the BOOT environment variable. Refer to the "Specify the Startup
Configuration File" section in the "Modifying, Downloading, and Maintaining Configuration Files"
chapter of the Configuration Fundamentals Configuration Guide for details on setting the
CONFIG_FILE variable.
When you use the boot system global configuration command, you affect only the running
Note
configuration. You must save the environment variable setting to your startup configuration to place the
information under ROM monitor control and for the environment variables to function as expected. Enter
the copy system:running-config nvram:startup-config command to save the environment variables
from your running configuration to your startup configuration.
You can view the contents of the BOOT environment variable using the show bootvar command. This
command displays the settings for these variables as they exist in the startup configuration as well as in
the running configuration if a running configuration setting differs from a startup configuration setting.
This example shows how to check the environment variables:
Router# show bootvar
BOOT variable = disk0:,1;sup-bootflash:,1;
CONFIG_FILE variable =
BOOTLDR variable =
Configuration register is 0x2102
Router#
For additional information (including configuration examples and troubleshooting information), see the
Tip

documents listed on this page:

http://www.cisco.com/en/US/products/hw/routers/ps368/tsd_products_support_series_home.html
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
3-26
OL-4266-08