Cisco WS-C2960S-48LPD-L Software Guide - Page 74
Booting a Specific Software Image, Controlling Environment Variables
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Modifying the Startup Configuration Chapter 3 Assigning the Switch IP Address and Default Gateway Booting a Specific Software Image By default, the switch attempts to automatically boot up the system using information in the BOOT environment variable. If this variable is not set, the switch attempts to load and execute the first executable image it can by performing a recursive, depth-first search throughout the flash file system. In a depth-first search of a directory, each encountered subdirectory is completely searched before continuing the search in the original directory. However, you can specify a specific image to boot up. Beginning in privileged EXEC mode, follow these steps to configure the switch to boot a specific image during the next boot cycle: Step 1 Step 2 Step 3 Step 4 Step 5 Command configure terminal boot system filesystem:/file-url end show boot copy running-config startup-config Purpose Enter global configuration mode. Configure the switch to boot a specific image in flash memory during the next boot cycle. • For filesystem:, use flash: for the system board flash device. • For file-url, specify the path (directory) and the name of the bootable image. Filenames and directory names are case sensitive. Return to privileged EXEC mode. Verify your entries. The boot system global command changes the setting of the BOOT environment variable. During the next boot cycle, the switch attempts to automatically boot up the system using information in the BOOT environment variable. (Optional) Save your entries in the configuration file. To return to the default setting, use the no boot system global configuration command. Controlling Environment Variables With a normally operating switch, you enter the boot loader mode only through a switch console connection configured for 9600 b/s. Unplug the switch power cord, and press the switch Mode button while reconnecting the power cord. You can release the Mode button a second or two after the LED above port 1 turns off. Then the boot loader switch: prompt appears. The switch boot loader software provides support for nonvolatile environment variables, which can be used to control how the boot loader, or any other software running on the system, behaves. Boot loader environment variables are similar to environment variables that can be set on UNIX or DOS systems. Environment variables that have values are stored in flash memory outside of the flash file system. Each line in these files contains an environment variable name and an equal sign followed by the value of the variable. A variable has no value if it is not listed in this file; it has a value if it is listed in the file even if the value is a null string. A variable that is set to a null string (for example, " ") is a variable with a value. Many environment variables are predefined and have default values. 3-14 Catalyst 2960 Switch Software Configuration Guide OL-8603-04
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