Cisco Catalyst 2950 Command Reference Manual page 637

Appendix B Catalyst 2950 and 2955 Switch Boot Loader Commands
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
OL-10102-01
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 service port 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 the software uses to read and
write a nonvolatile copy of the system configuration.
CONFIG_BUFSIZE—Resets the buffer size that the software uses to hold
a copy of the configuration file in memory.
BAUD—Resets the rate in bits per second (bps) used for the service port. The
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 the software
that are loaded, including the helper image. This variable is used only for
internal development and testing.
PASSWD_RECOVERY—Resets the password recovery option.
Catalyst 2950 and Catalyst 2955 Switch Command Reference
unset
B-25