Config_File Environment Variable; Controlling Environment Variables - Cisco 7609 Configuration Manual

Modifying the Supervisor Engine Startup Configuration

CONFIG_FILE Environment Variable

For Class A Flash file systems, the CONFIG_FILE environment variable specifies the file system and
filename of the configuration file to use for initialization (startup). Valid file systems can include
nvram:, slot0:, and sup-bootflash:.
For detailed file management configuration information, refer to the Cisco IOS Configuration
Fundamentals Configuration Guide at this URL:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios121/121cgcr/fun_c/index.htm
After you save the CONFIG_FILE environment variable to your startup configuration, the router checks
the variable upon startup to determine the location and filename of the configuration file to use for
initialization.
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
the setup Command" section on page 3-2

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, BOOTLDR, and CONFIG_FILE environment
variables, use the boot system, boot bootldr, and boot config global configuration commands.
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, boot bootldr, and boot config global configuration commands, you
Note
affect only the running configuration. You must save the environment variable settings 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, BOOTLDR, and the CONFIG_FILE environment variables
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 BOOT, BOOTLDR, and the CONFIG_FILE environment
variables:
Router# show bootvar
BOOT variable = slot0:c6sup22-jsv-mz.121-5c.EX.bin,1;
CONFIG_FILE variable does not exist
BOOTLDR variable = bootflash:c6msfc2-boot-mz.121-3a.E4
Configuration register is 0x2
Router#
To display the contents of the configuration file pointed to by the CONFIG_FILE environment variable,
enter the more nvram:startup-config command.
Cisco 7600 Series Router Cisco IOS Software Configuration Guide—12.1E
3-26
Chapter 3 Configuring the Cisco 7600 Series Router for the First Time
for more information on the setup command facility.
"Using the Setup Facility or
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