Controlling Environment Variables - Cisco 4500M Software Manual

Modifying the Supervisor Engine Startup Configuration
Configuring Flash Memory
To configure your switch to boot from Flash memory, perform the following procedure. (Refer to the
appropriate hardware installation and maintenance publication for complete instructions on installing
the hardware.)
Copy a system image to Flash memory using TFTP or other protocols. Refer to the "Cisco IOS File
Step 1
Management" and "Loading and Maintaining System Images" chapters in the Cisco IOS Configuration
Fundamentals Configuration Guide, Release 12.2, at the following URL:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fun_c/fcprt2/fcd203.htm
Configure the system to boot automatically from the desired file in Flash memory. You might need to
Step 2
change the configuration register value. See the
Command" section on page
Step 3 Save your configurations.
Power cycle and reboot your system to verify that all is working as expected.
Step 4

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 and BOOTLDR variables, use the boot system and
boot bootldr global configuration commands, respectively. 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.
Note When you use the boot system and boot bootldr global configuration commands, you affect only the
running configuration. To save the configuration for future use, you must save the environment variable
settings to your startup configuration, which places the information under ROM monitor control. 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 and BOOTLDR variables using the show bootvar command.
This command displays the settings for these variables as they exist in the startup configuration and in
the running configuration if a running configuration setting differs from a startup configuration setting.
This example shows how to check the BOOT and BOOTLDR variables on the switch:
Switch# show bootvar
BOOTLDR variable = bootflash:cat4000-is-mz,1;
Configuration register is 0x0
Switch#
Software Configuration Guide—Release 12.2(25)EW
3-24
"Modifying the Boot Field and Using the boot
3-20, for more information on modifying the configuration register.
Chapter 3 Configuring the Switch for the First Time
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