Cisco Catalyst 3750-E - Page 118

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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 3 Assigning the Switch IP Address and Default Gateway
Modifying the Startup Configuration
You can change the settings of the environment variables by accessing the boot loader or by using Cisco
IOS commands. Under normal circumstances, it is not necessary to alter the setting of the environment
variables.
Note For complete syntax and usage information for the boot loader commands and environment variables,
see the command reference for this release.
Table 3-4 describes the function of the most common environment variables.
Ta b l e 3-4 Environment Variables
Variable Boot Loader Command Cisco IOS Global Configuration Command
BOOT set BOOT f
ilesystem:/file-url ...
A semicolon-separated list of executable files
to tr
y to load and execute when automatically
booting. If the BOOT environment variable is
not set, the system attempts to load and execute
the first executable image it can find by using a
recursive, depth-first search through the flash
file system. If the BOOT variable is set but the
specified images cannot be loaded, the system
attempts to boot up the first bootable file that it
can find in the flash file system.
boot system {file
system:/file-url ...| switch
{number | all}}
Note The switch {number | all} keywords are
supported only on Catalyst 3750-E
switches.
Specifies the Cisco IOS image to load during the
n
ext boot cycle and the stack members on which
the image is loaded. This command changes the
setting of the BOOT environment variable.
MANUAL_BOOT set MANUAL_BOOT yes
Decides whether the switch automatically or
m
anually boots.
Valid values are 1, yes, 0, and no. If it is set to
n
o or 0, the boot loader attempts to
automatically boot up the system. If it is set to
anything else, you must manually boot up the
switch from the boot loader mode.
boot manual
Enables manually booting the switch during the
n
ext boot cycle and changes the setting of the
MANUAL_BOOT environment variable.
The next time you reboot the system, the switch is
i
n boot loader mode. To boot up the system, use
the boot flash:filesystem:/file-url boot loader
command, and specify the name of the bootable
image.
CONFIG_FILE set CONFIG_FILE fl
ash:/file-url
Changes the filename that Cisco IOS uses to
r
ead and write a nonvolatile copy of the system
configuration.
boot config-file flash:/fil
e-url
Specifies the filename that Cisco IOS uses to read
an
d write a nonvolatile copy of the system
configuration. This command changes the
CONFIG_FILE environment variable.