Cisco Catalyst 3550 Command Reference Manual page 718

unset
unset
Use the unset boot loader command to reset one or more environment variables.
Under normal circumstances, it is not necessary to alter the setting of the environment variables.
Note
Syntax Description
variable
Command Modes
Boot loader
Catalyst 3550 Multilayer Switch Command Reference
A-24
unset variable ...
Use one of these keywords for variable:
MANUAL_BOOT—Decides whether the switch automatically or manually
boots.
BOOT—Resets the list of executable files to try 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 the first bootable file that it can find in the flash file system.
ENABLE_BREAK—Decides whether the automatic boot process can be
interrupted by using the Break key on the console after the flash file system
has been initialized.
HELPER—A semicolon-separated list of loadable files to dynamically load
during the boot loader initialization. Helper files extend or patch the
functionality of the boot loader.
PS1—A string that is used as the command-line prompt in boot loader mode.
CONFIG_FILE—Resets the filename that Cisco IOS uses to read and write
a nonvolatile copy of the system configuration.
CONFIG_BUFSIZE—Resets the buffer size that Cisco IOS uses to hold a
copy of the configuration file in memory.
BAUD—Resets the rate in bits per second (bps) used for the console. The
Cisco IOS software inherits the baud rate setting from the boot loader and
continues to use this value unless the configuration file specifies another
setting.
BOOTHLPR—Resets the name of the Cisco IOS helper image that is first
loaded into memory so that it can then load a second Cisco IOS image into
memory and launch it. This variable is used only for internal development and
testing.
HELPER_CONFIG_FILE—Resets the name of the configuration file to be
used by the Cisco IOS helper image. If this is not set, the file specified by the
CONFIG_FILE environment variable is used by all versions of Cisco IOS
that are loaded, including the helper image. This variable is used only for
internal development and testing.
Appendix A Catalyst 3550 Switch Boot Loader Commands
OL-8566-02